RE: Latest issue of the ?Cadrans solaires pour tous? magazine

[Kenneth Lee]

The URL for the PDF is
https://www.cadrans-solaires.info/wp-content/uploads/2024/05/mag-CSpour-tous-n12.pdf

Most of the content is in French, to translate to English, download the PDF,
Go to google's translation service
https://translate.google.com/?sl=auto=en=docs=en
Drag/Drop the french PDF into the left side.
Click translate,
Click download translation,
Enjoy ...
Thx Roger!

Rgds
Kenneth
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Re: A sundial in Seville

[lvadillo]

Here you can see the incorrect gnomon reposition, quite well anti-vandalism!
https://relojesdesol.info/gallery2/gallery/v/espana/and/sev/ES_AND_SEV_Sevilla-009-03_Plaza-de-America_Wiki4.jpg.html
in the following album picture with the original gnomon.

Regards, Luis

El 22/03/2024 a las 15:40, Douglas Bateman via sundial escribió:

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Re: A sundial in Seville

[Fabio Savian]

it is also here:

www.sundialatlas.eu/atlas.php?sun=ES877

Fabio Savian


Il 22/03/2024 15:40, Douglas Bateman via sundial ha scritto:

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--
Fabio Savian
fabio.sav...@nonvedolora.it
UTC +1, DST +2, 45° 34' 9'' N, 9° 9' 53'' E
Paderno Dugnano, Milano, Italy

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Re: A sundial in Seville

[Patrick Powers via sundial]

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Plaza de America. 
https://elsolieltemps.com/php/rutes/rutes_fitxa.php?rutes_ID=20=english

On 22/03/2024 14:41:08, Douglas Bateman via sundial  
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RE: Photograph of the Princess of Wales

[R. Hooijenga via sundial]

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Aren't we in danger here of confusing 'light' and 'source of light'?
The light from the sun, for instance, is traveling away from the sun -
toward a dial surface, for example.
The shadow from an object is also pointing away from the sun - toward the
dial surface for example, if from the gnomon.
You could interpret that as 'being in the same direction'.

Rudolf, 52 30 N 4 40 E

-Oorspronkelijk bericht-
Van: sundial  Namens Frank King
Verzonden: maandag 11 maart 2024 10:02
Aan: Sundial List 
Onderwerp: Photograph of the Princess of Wales

Dear All,

There is much talk about the recent photograph of the Princess of Wales and
her children.

In one newspaper I read that "a former digital forensics officer for Dorset
Police said...

   'In a true image, the shadows will all be
   in the same direction as the light'"

Huh!

He has clearly never looked at a sundial!

He may mean 'in the opposite direction' but that isn't true either.
Moreover, shadows do not necessarily align.

A Double Horizontal sundial works precisely because its two shaodws are
(generally)in different directions.

Of course, a shadow CAN be in the same direcion as the light.  I'll leave
that as an exercise for the reader :-)

Frank King
Cambridge, UK


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RE: sundial Digest, Vol 215, Issue 2

[John Foad]

As Professor Joad used to say, it all depends what you mean by ‘direction’.  A 
shadow simply falls on a surface.  It doesn’t have a direction.

We need a clearer statement of the question.

John Foad

 

 

From: sundial On Behalf Of John Lynes
Sent: Monday, March 11, 2024 6:24 PM
To: Bill Gottesman 
Cc: sundial@uni-koeln.de
Subject: Re: sundial Digest, Vol 215, Issue 2

 

I think there's a simpler solution.

In the UK at noon the shadow of the style on a horizontal sundial faces North - 
away from the sun.  Turn the style through 180 degrees in a horizontal plane, 
and its shadow at noon will face South - towards the sun!

John Lynes

 

On Mon, 11 Mar 2024 at 17:12, Bill Gottesman mailto:billgottes...@gmail.com> > wrote:

My guess on this one (without using mirrors):

Point the  bottom of an empty can at the sun.  The shadow inside the can now 
points in the direction of the sun, though the definition of "in the direction 
of the sun" in this case is debatable.

-Bill

 

On Mon, Mar 11, 2024 at 9:33 AM Chris Lusby Taylor mailto:clusbytay...@gmail.com> > wrote:

This reader has so far failed to see how a shadow can be in the same direction 
as the light source, if by that Frank means that it is between the object and 
the light. Perhaps Frank will enlighten us at next month's annual British 
Sundial Society Conference.


Date: Mon, 11 Mar 2024 09:01:46 +
From: Frank King mailto:f...@cl.cam.ac.uk> >
Of course, a shadow CAN be in the same direcion as the light.  I'll leave that 
as an exercise for the reader :-)

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Re: sundial Digest, Vol 215, Issue 2

[John Lynes]

I think there's a simpler solution.
In the UK at noon the shadow of the style on a horizontal sundial faces
North - away from the sun.  Turn the style through 180 degrees in a
horizontal plane, and its shadow at noon will face South - towards the sun!
John Lynes

On Mon, 11 Mar 2024 at 17:12, Bill Gottesman 
wrote:

> My guess on this one (without using mirrors):
> Point the  bottom of an empty can at the sun.  The shadow inside the can
> now points in the direction of the sun, though the definition of "in the
> direction of the sun" in this case is debatable.
> -Bill
>
> On Mon, Mar 11, 2024 at 9:33 AM Chris Lusby Taylor 
> wrote:
>
>> This reader has so far failed to see how a shadow can be in the same
>> direction as the light source, if by that Frank means that it is between
>> the object and the light. Perhaps Frank will enlighten us at next month's
>> annual British Sundial Society Conference.
>>
>>>
>>> Date: Mon, 11 Mar 2024 09:01:46 +
>>> From: Frank King 
>>> Of course, a shadow CAN be in the same direcion as the light.  I'll
>>> leave that as an exercise for the reader :-)
>>>
>> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
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Re: sundial Digest, Vol 215, Issue 2

[Bill Gottesman]

My guess on this one (without using mirrors):
Point the  bottom of an empty can at the sun.  The shadow inside the can
now points in the direction of the sun, though the definition of "in the
direction of the sun" in this case is debatable.
-Bill

On Mon, Mar 11, 2024 at 9:33 AM Chris Lusby Taylor 
wrote:

> This reader has so far failed to see how a shadow can be in the same
> direction as the light source, if by that Frank means that it is between
> the object and the light. Perhaps Frank will enlighten us at next month's
> annual British Sundial Society Conference.
>
>>
>> Date: Mon, 11 Mar 2024 09:01:46 +
>> From: Frank King 
>> Of course, a shadow CAN be in the same direcion as the light.  I'll leave
>> that as an exercise for the reader :-)
>>
>
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Re: sundial Digest, Vol 215, Issue 2

[Chris Lusby Taylor]

Re:  Photograph of the Princess of Wales (Frank King)
Frank is being his usual pedantic self, which is always welcome, but the
police statement can more charitably be taken to say that shadows fall in a
continuation of the straight line from the light source to the illuminated
object. The edge of a shadow is always in line with an edge of an object
and the light source. If a featureless item such as the edge of a gnomon
casts a shadow you can't tell which point along the edge cast each point of
shadow edge. Distortion created by camera lenses may render some straight
lines as curves, but it seems to me fair to use ray tracing to spot
photographs that have been tampered with.

Since the sun is, more or less, a point source, I would certainly expect
all rays traced back from shadows, past the object, to converge on the
light source.

As for the double horizontal, yes the edges of the two shadows point in
different directions but so do the shadows on the dial of the two hands of
a clock. It doesn't seem to me a meaningful point. By the way, why was the
replacement gnomon on the double horizontal in the current BSS Bulletin
made so long? Ray tracing indicates its top section could never cast a
shadow on the dial.

This reader has so far failed to see how a shadow can be in the same
direction as the light source, if by that Frank means that it is between
the object and the light. Perhaps Frank will enlighten us at next month's
annual British Sundial Society Conference.

Chris Lusby Taylor

On Mon, Mar 11, 2024 at 11:00 AM  wrote:

> Send sundial mailing list submissions to
> sundial@uni-koeln.de
>
> To subscribe or unsubscribe via the World Wide Web, visit
> https://lists.uni-koeln.de/mailman/listinfo/sundial
> or, via email, send a message with subject or body 'help' to
> sundial-requ...@uni-koeln.de
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> You can reach the person managing the list at
> sundial-ow...@uni-koeln.de
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of sundial digest..."
>
>
> Today's Topics:
>
>1. Photograph of the Princess of Wales (Frank King)
>
>
> --
>
> Message: 1
> Date: Mon, 11 Mar 2024 09:01:46 +
> From: Frank King 
> To: Sundial List 
> Subject: Photograph of the Princess of Wales
> Message-ID: 
> Content-Type: text/plain; charset=us-ascii
>
> Dear All,
>
> There is much talk about the recent photograph
> of the Princess of Wales and her children.
>
> In one newspaper I read that "a former digital
> forensics officer for Dorset Police said...
>
>'In a true image, the shadows will all be
>in the same direction as the light'"
>
> Huh!
>
> He has clearly never looked at a sundial!
>
> He may mean 'in the opposite direction' but
> that isn't true either.  Moreover, shadows
> do not necessarily align.
>
> A Double Horizontal sundial works precisely
> because its two shaodws are (generally)in
> different directions.
>
> Of course, a shadow CAN be in the same direcion
> as the light.  I'll leave that as an exercise
> for the reader :-)
>
> Frank King
> Cambridge, UK
>
>
>
>
> --
>
> Subject: Digest Footer
>
> ___
> sundial mailing list
> sundial@uni-koeln.de
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
> --
>
> End of sundial Digest, Vol 215, Issue 2
> ***
>


-- 

Chris Lusby Taylor
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Re: World Sundial Day

[ro...@torrenti.net]

This is a clever initiative that our group and magazine will support

All the best
Roger Torrenti

Author of the MOOC cadrans solaires<https://www.cadrans-solaires.info/> (free 
online course on sundials)
Founder and editorial manager of the « Cadrans solaires pour tous » (sundials 
for all) magazine
Former President and active member of the Commission des Cadrans Solaires 
(Société Astronomique de France)<https://ccs.saf-astronomie.fr/>


De : sundial  de la part de lvadillo 

Date : jeudi, 22 février 2024 à 21:35
À : sundial@uni-koeln.de 
Objet : Re: World Sundial Day
The spanish AARS and myself are in favor of the WSD initiative. It may be a 
boost to sundials interest all around the world.
Counting with your support (members and associations).

You can also support it voting at Change.org:  https://chng.it/g8rkJVQYk6

Please diseminate.
Thanks and regards, Luis E. Vadillo
https://relojesdesol.info


P.D.: The WSD petition text in english:

Reason ► Sundials have been the most common form used for measuring time by all 
civilizations until the appearance of mechanical clocks, even coexisting with 
them. Sundials represent the union of disciplines as disparate as Astronomy, 
Mathematics, Geography, etc. They have an undoubted didactic value in teaching 
astronomy to young people and as an object present in public spaces, in places 
where people can better understand our relationship with the Sun. They bring 
together Science and Art, the greatest exponents of human Reason and Creation

Claim ► They are differentiated and unique pieces of all the peoples of the 
Earth and therefore need special legal protection. We promote its inventory 
globally and the creation of a unique figure that legally protects historical 
and modern sundials.

Why the establishment of a World Day ► With the celebration of World Sundial 
Day, we intend to raise awareness among citizens about the importance that 
sundials have had in all cultures, making information available to them in 
order to activate the political will and resources to address their protection 
as fundamental and differentiated elements of World Heritage.

Proposed date of celebration ► We propose the celebration of World Sundial Day 
on the March Equinox, the day of the year on which the shadow in sundials casts 
a straight line on a plane and the day has a duration approximately equal to 
the one at night In astronomy it's the Aries point, the origin of right 
ascension with the Sun in the plane of the Earth's equator. Already in Roman 
times, the month of March was the month in which the year began.

Note: This petition has arisen from the website "Reloj Andalusí" 
(www.relojandalusi.org<http://www.relojandalusi.org>) coordinated by Esteban 
Martínez Almirón, but has the support of numerous gnomonic associations, fans 
and web pages or blogs related to sundials and astronomy.

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Re: World Sundial Day

[lvadillo]

The spanish AARS and myself are in favor of the WSD initiative. It may be a 
boost to sundials interest all around the world.
Counting with your support (members and associations).

You can also support it voting at Change.org: https://chng.it/g8rkJVQYk6

Please diseminate.
Thanks and regards, Luis E. Vadillo
https://relojesdesol.info


P.D.: The WSD petition text in english:

Reason ► Sundials have been the most common form used for measuring time by all 
civilizations until the appearance of mechanical clocks, even coexisting with 
them. Sundials represent the union of disciplines as disparate as Astronomy, 
Mathematics, Geography, etc. They have an undoubted didactic value in teaching 
astronomy to young people and as an object present in public spaces, in places 
where people can better understand our relationship with the Sun. They bring 
together Science and Art, the greatest exponents of human Reason and Creation

Claim ► They are differentiated and unique pieces of all the peoples of the 
Earth and therefore need special legal protection. We promote its inventory 
globally and the creation of a unique figure that legally protects historical 
and modern sundials.

Why the establishment of a World Day ► With the celebration of World Sundial 
Day, we intend to raise awareness among citizens about the importance that 
sundials have had in all cultures, making information available to them in 
order to activate the political will and resources to address their protection 
as fundamental and differentiated elements of World Heritage.

Proposed date of celebration ► We propose the celebration of World Sundial Day 
on the March Equinox, the day of the year on which the shadow in sundials casts 
a straight line on a plane and the day has a duration approximately equal to 
the one at night In astronomy it's the Aries point, the origin of right 
ascension with the Sun in the plane of the Earth's equator. Already in Roman 
times, the month of March was the month in which the year began.

Note: This petition has arisen from the website "Reloj Andalusí" 
(www.relojandalusi.org ) coordinated by Esteban Martínez 
Almirón, but has the support of numerous gnomonic associations, fans and web pages or blogs 
related to sundials and astronomy.

---
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Re: World Sundial Day

[Martha A. Villegas V. via sundial]

Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die
eigentliche Nachricht steht dadurch in einem Anhang.

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 Dear Sundial friends,
As Manolo Pizarro already wrote in this list, Spanish gnomonist Esteban 
Martínez has launched the idea to stablish the World Sundial Day.
You can find this initiative in his web page Reloj Andalusí - Página principal 
(relojandalusi.org)
Following,  there is a translation of the text supporting his proposal.
Reason ► Sundials have been the most common form used for measuring time by 
allcivilizations until the appearance of mechanical clocks, even coexisting 
with them. Sundialsrepresent the union of disciplines as disparate as 
Astronomy, Mathematics, Geography, etc.They have an undoubted didactic value in 
teaching astronomy to young people and as anobject present in public spaces, in 
places where people can better understand our relationshipwith the Sun. They 
bring together Science and Art, the greatest exponents of human Reasonand 
Creation
Claim ► They are differentiated and unique pieces of all the peoples of the 
Earth andtherefore need special legal protection. We promote its inventory 
globally and the creation of aunique figure that legally protects historical 
and modern sundials.
Why the establishment of a World Day ► With the celebration of World Sundial 
Day, weintend to raise awareness among citizens about the importance that 
sundials have had in allcultures, making information available to them in order 
to activate the political will andresources to address their protection as 
fundamental and differentiated elements of WorldHeritage
Proposed Date of Celebration ► We propose the celebration of World Sundial Day 
on theSpring Equinox, the first day of the year on which the shadow in sundials 
casts a straight lineon a plane. And it is on the first of the equinoxes 
because already in Roman times the month ofMarch was the month in which the 
year began. In this year 2024 the date is March 20.

Please share this project with friends, schools and groups of interest in this 
area.Regards to all
José C.Montes y Martha A Villegas from México.


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Re: Finding GB patents (off list)

[John Pickard via sundial]

Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die
eigentliche Nachricht steht dadurch in einem Anhang.

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text is therefore in an attachment.--- Begin Message ---

Good morning on the last day of 2023.

Many thanks to those who responded with suggestions about finding early 
GB patents. Although excellent, they did not help me with either my 
specific problem, or the more general one of the almost impenetrable 
opacity of the GB IP Office.


So I'm still looking for a professional searcher. Ah well, that's next 
year's problem!


I wish everyone happiness and sunny skies in 2024, and I hope that it's 
somewhat better than the appalling turmoil of 2023.


Cheers, John.

Dr John Pickard.

On 02-December-2023 19:15, John Pickard wrote:


Good afternoon,

As part of my research into the history of Australian rural fences (I 
said it was off-list!), I am trying to get copies of GB patents for 
fence-related items. Although I am pretty good at searching, I find GB 
patents the most difficult to find.  Espacenet picks up some, but only 
a fraction of the many that I am certain exist.


Many GB iron-makers manufactured a range of posts etc. and many were 
exported to Australia in the 19th and early 20th centuries. I need the 
patents to finish a book I am compiling on Australian fence posts and 
droppers to complement my 2022 book "Australian wire strainers".


My specific question: can anyone suggest the name of a company / sole 
trader who searches for GB patents? I'm quite happy to pay a 
reasonable amount in return for a complete set of PDFs of GB patents 
which match my keywords (fenc*, wire, post, strainer, etc.) in either 
the titles or specifications. I also have names of many of the 
patentees marked on various posts etc. manufactured in GB, or listed 
in catalogues.


Any suggestions would be most welcome!

Many thanks, John

Dr John Pickard

www.australianfencepublishing.com.au
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Re: Substitute for DeltaCad?

[Simon WS]

Freecad and nanocad work well, power draw also works except when I used it,
I had to write my own trig functions. However I never exported the dial
plates from them as I can and still do use deltacad. I have also used
progecad. My book "Programming Shadows" has sample code for them, as well
as other languages and systems, it is free to download on
www.illustratingshadows.com
Simon

On Sun, Nov 26, 2023, 17:29 Bill Gottesman  wrote:

> Hello All,
>
> DeltaCad does not function fully on my Mac M1Pro (Mac silicon based).  It
> will not save in .dxf format, so I can't move things out of the .dc
> proprietary DeltaCad files into Adobe Illustrator.
> DeltaCad has been discontinued by the developer.
> Does anyone have a work-around, or a different simple-to-use 2-D CAD
> program to recommend?  I really like DeltaCad but I don't see how to get
> around this.
>
> Best,
> Bill Gottesman
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
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Re: Winter issue of the “Cadrans solaires pour tous” magazine

[ro...@torrenti.net]

Thank you Dennis,

The English translation of the solution of the “énigme” provided in the 
magazine is “You may have thought of a Mass dial but it is not one… A Mass dial 
is typically made up (photo below) of a semi-circle (sometimes a complete 
circle) divided into regular sectors and with a gnomon perpendicular to the 
wall, fixed in the center of the circle. It does not give solar time but 
indicates the start of liturgical acts. What appears in the photo taken in 
Scotland is not a Mass dial but a leveling mark, often installed on the walls 
of public buildings so that surveyors have fixed benchmarks (position and 
height) in their measurements. Such a leveling mark can take very different 
forms: small metal cylinder sealed in the wall, decorative plaque, etc.”

I hope this clarifies the confusion created, for those readers who are not 
fluent in French, by the fact that the photo of a Mass dial goes with the 
solution. 

Best regards
Roger



De : dennis.cowan 
Date : dimanche, 26 novembre 2023 à 10:48
À : ro...@torrenti.net , Sundial List 
Objet : RE: Winter issue of the “Cadrans solaires pour tous” magazine
Dear Roger

With reference to une enigme on page 34, this is an OS benchmark.


OS benchmarks are survey marks that were used by the Ordnance Survey to make 
maps. They can be found on walls and buildings across Britain and were a way of 
recording height at a given point.
Google "OS benchmark" for more information.

Regards
Dennis Cowan




Sent from my Mobile


 Original message 
From: ro...@torrenti.net
Date: 23/11/2023 06:48 (GMT+00:00)
To: Sundial List 
Subject: Winter issue of the “Cadrans solaires pour tous” magazine

Dear colleagues,

I am very glad to inform you that the Winter issue of the “Cadrans solaires 
pour tous” magazine is now available for free download from 
https://www.cadrans-solaires.info/le-magazine/

Best regards

Roger Torrenti

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RE: Winter issue of the “Cadrans solaires pour tous” magazine

[dennis.cowan via sundial]

Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die
eigentliche Nachricht steht dadurch in einem Anhang.

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text is therefore in an attachment.--- Begin Message ---
Dear RogerWith reference to une enigme on page 34, this is an OS benchmark.  OS 
benchmarks are survey marks that were used by the Ordnance Survey to make maps. 
They can be found on walls and buildings across Britain and were a way of 
recording height at a given point.Google "OS benchmark" for more 
information.RegardsDennis Cowan Sent from my Mobile
 Original message From: ro...@torrenti.net Date: 23/11/2023  
06:48  (GMT+00:00) To: Sundial List  Subject: Winter 
issue of the “Cadrans solaires pour tous” magazine 

Dear colleagues,
 
I am very glad to inform you that the Winter issue of the “Cadrans solaires 
pour tous” magazine is now available for free download from
https://www.cadrans-solaires.info/le-magazine/
 
Best regards
 
Roger Torrenti
 



--- End Message ---
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Re: Re : Difference between types of equinox

[Steve Lelievre]

My thanks go to Bill and Hervé for responding to my equinox question.


The information they provided indicates that the change in definition of 
astronomical equinox, from delta = 0 to lambda = 0/180, had no practical 
impact as far as sundialing is concerned (only a few seconds). For the 
difference between astronomical equinox and temporal equinox, the French 
article recommended by Hervé explains the long-term drift of the 
solstices and astronomical equinoxes, and I now see the direct effect 
that phenomenon would have on temporal equinoxes (the midpoint between 
solstices.)



As well, I took Bill's hint and found a table of solstice and 
(astronomical) equinox dates and times for years 2001 to 2099. I used 
http://www.russellcottrell.com/blog/solarEvents.htm.  From the data I 
produced the enclosed graph of the time delay between the astronomical 
and the temporal equinox. Assuming I did the calculations right, then in 
the present day there are about 1.87 to 1.9 days between the two events. 
If we think in terms of whole days, those differences will correspond to 
one or two calendar days depending on when exactly each instant occurs 
within its day.



Cheers,

Steve









On 2023-09-05 2:23 a.m., Hervé Guillemet wrote:

Hi Steve,

I think that some answers to your questions can easily be found on the 
following link of the French "Institut de Mécanique Céleste et de 
Calcul des Éphémérides" (IMCCE) :

https://www.imcce.fr/newsletter/html/newsletter.html#current-article2
They publish (in French) a free information letter every month and in 
March and September it contains the timing of the equinox with a 
picture, easy to understand even if you do not speak French.


They remind that in the northern hemisphere the Autumn equinox is when 
the geocentric longitude of the Sun is exactly equal to 180° (and 0° 
for the Spring).  As indicated there is a difference of a few seconds 
with the time when its declination is equal to 0° and when its right 
ascension is equal to 12h.


The previous information letters can be accessed via :
https://www.imcce.fr/lettre-information/
and the data can be retrieved each March and September month

Best regards Hervé

*De: *"Steve Lelievre" 
*À: *"Sundial List" 
*Envoyé: *Mardi 5 Septembre 2023 01:23:15
*Objet: *Difference between types of equinox

Hello,

 From what I've read recently, there are three variants of an equinox:

- Modern astronomical definition: apparent geocentric longitude of the
sun is 0 or 180 degrees.

- The older astronomical definition (often used in dialling) : solar
declination is 0 degrees.

- 'Temporal equinox': halfway between solstices as measured by passage
of time, which is the lay/folk/traditional understanding

I'd like to know:

How big are the time intervals between these three types of equinoxes?

How much do these intervals change as the years or centuries go by, if
at all?

Thanks,

Steve




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Re : Difference between types of equinox

[Hervé Guillemet]

Hi Steve, 


I think that some answers to your questions can easily be found on the 
following link of the French " Institut de Mécanique Céleste et de Calcul des 
Éphémérides" ( IMCCE) : 

https://www.imcce.fr/newsletter/html/newsletter.html#current-article2 

They publish (in French) a free information letter every month and in March and 
September it contains the timing of the equinox with a picture, easy to 
understand even if you do not speak French. 



They remind that in the northern hemisphere the Autumn equinox is when the 
geocentric longitude of the Sun is exactly equal to 180° (and 0° for the 
Spring). As indicated there is a difference of a few seconds with the time when 
its declination is equal to 0° and when its right ascension is equal to 12h. 



The previous information letters can be accessed via : 
https://www.imcce.fr/lettre-information/ 
and the data can be retrieved each March and September month 



Best regards Hervé 
- Mail original -

De: "Steve Lelievre"  
À: "Sundial List"  
Envoyé: Mardi 5 Septembre 2023 01:23:15 
Objet: Difference between types of equinox 

Hello, 

>From what I've read recently, there are three variants of an equinox: 

- Modern astronomical definition: apparent geocentric longitude of the 
sun is 0 or 180 degrees. 

- The older astronomical definition (often used in dialling) : solar 
declination is 0 degrees. 

- 'Temporal equinox': halfway between solstices as measured by passage 
of time, which is the lay/folk/traditional understanding 

I'd like to know: 

How big are the time intervals between these three types of equinoxes? 

How much do these intervals change as the years or centuries go by, if 
at all? 

Thanks, 

Steve 




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Re: Difference between types of equinox

[Bill Gottesman]

I seem to recall Fred contributing to a similar conversation a few years
ago.  Speaking from ignorance, I think the sun will not be at exactly 0
declination at 180 longitude because the moon can pull the earth above or
below the ecliptic depending on the lunar orbit. I think the effect is
tiny, and only affects the timing of the zero degree declination definition
of equinox by maybe a minute?

Here is a paste from wikipedia:
The modern definition of equinox is the instant when the Sun's apparent
geocentric ecliptic longitude is 0° (northward equinox
) or 180° (southward equinox
).[34]
[35]
[36]
 Note that at that
moment, its latitude will not be exactly zero, since Earth is not exactly
in the plane of the ecliptic. Its declination will also not be exactly
zero, so the scientific definition is slightly different from the
traditional one. The *mean* ecliptic is defined by the barycenter
 of Earth and the Moon combined,
to minimize the fact that the orbital inclination of the Moon causes the
Earth to wander slightly above and below the ecliptic.[38]


Oops, I did not answer your question, which was about the time intervals,
not the cause.  Sounds like a job for good astronomy modeling software -
maybe Stellarium?

-Bill

On Mon, Sep 4, 2023 at 7:25 PM Steve Lelievre <
steve.lelievre.can...@gmail.com> wrote:

> Hello,
>
>  From what I've read recently, there are three variants of an equinox:
>
> - Modern astronomical definition: apparent geocentric longitude of the
> sun is 0 or 180 degrees.
>
> - The older astronomical definition (often used in dialling) : solar
> declination is 0 degrees.
>
> - 'Temporal equinox': halfway between solstices as measured by passage
> of time, which is the lay/folk/traditional understanding
>
> I'd like to know:
>
> How big are the time intervals between these three types of equinoxes?
>
> How much do these intervals change as the years or centuries go by, if
> at all?
>
> Thanks,
>
> Steve
>
>
>
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
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Re: [SPAM] Largest stone sundial?

[Willy Leenders]

Dan-George,

The earth globe itself.

Willy Leenders
Hasselt Belgium

> Op 9 aug. 2023, om 12:30 heeft Dan-George Uza  het 
> volgende geschreven:
> 
> Hello,
> 
> Does anybody know what the largest one-piece stone sundial in the world is?
> 
> Thanks,
> 
> 
> -- 
> Dan-George Uza
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
> 

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Re: Interesting Moon Dial

[Mark Montgomery via sundial]

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 Hello Siegfried,
This is a wonderful dial.  The construction of this moon dial is given by 
Jacques Ozanam in 1693 in his "Cursus Mathematicus: or A Complelat Course of 
the Mathematicks."  Vol V Part III, "A  Treatise of Gnomonicks", Problem XX. 
This work is available from the NASS website Shadow Catchers series.
To read the dial you must know the age of the moon, or number of days since the 
last new moon.  The lunar age is given next to the meridian (noon) line with 
1-15 on the left side and 16-29 on the right side.  These numbers apply to the 
lines perpendicular to the meridian.  Find the line for the current lunar age 
and locate where the moon's shadow intersects this lunar age line.  There will 
be a slanted or curved line close to the intersection.  This is the local solar 
time line.  Follow the curved line the the edge of the dial to read the local 
solar time from the moon's shadow.
Hope this helps,Mark


On Monday, July 10, 2023 at 06:17:46 AM CDT, siegfried.netzb...@t-online.de 
 wrote:  
 
 
Dear sundial friends,


came across an interesting moon dial which is quite different from all the 
other moon dials I did see up to now 
(https://kabinett.mapublishing-lab.uni-koeln.de/objekte/monduhr).  However: I 
cannot read it, neither do I understand the way they calculated the lines on 
the dial to (may be) read off the time. 

The dial does not have the usual  numeric list where you can determine the age 
of the moon with the aid of the size of the illuminated moon. The age of the 
moon, i.e. the angle between moon and sun is needed to determine time using the 
moon shadow on a sun dial at night.


How do you read this dial and what is the basis (theory) for the lines to read 
of the time on this dial? Is there someone who can help? I would be very 
thankful for any help or advice.


Thank You for Your help!

Regards

Siegfried Netzband



 

 

  

Siegfried Netzband

Hebelstr. 12

75233 Tiefenbronn

Tel: 07234 2802

Fax: 07234 942909

Mob: 0151 53083636 / 0160 1531634

E-Mail: siegfried.netzb...@t-online.de

Skype: siegfried75233

www.ferienhaus-frieseneck.de

 

 

 

 
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RE: Off topic: English text explanation please

[R. Hooijenga via sundial]

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eigentliche Nachricht steht dadurch in einem Anhang.

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Hello all,

I am very happy with all the kind and insightful responses I received to my
off-topic question.
It looks like the easiest 'fix' is to replace 'to' with 'like to' or 'which
compares to'. That the one is to be taken positive, the other negative, is
implied: with heaven and hell, few would find that unclear.

I read German, and so the extra text example was a big help.
And of course, I looked up the wonderful 'Tobacco'-song. I had not heard or
seen it before, and quite enjoyed it.

Thank you to all the contributors,
And for everyone on the List to allow this short detour.

Rudolf Hooijenga
52-30 N 4-40 E


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RE: Off topic: English text explanation please

[R. Hooijenga via sundial]

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Steve, Peter, Jack,

Thanks so much for your replies. I’m in a bit of haste now, but will come back 
on them soon.

Rgds, Rudolf

 

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RE: Off topic: English text explanation please

[Jack Aubert via sundial]

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I am a serious amateur musician, but unlike Peter, do not really enjoy anything 
earlier than late baroque.  I am also a word freak and this query sent me down 
some interesting linguistic and etymologic rabbit holes.  

 

It is only stating the obvious to observer that poetry is ipso facto ambiguous; 
a line or phrase can mean several things simultaneously or be incomprehensible 
to most (or all) people.  It is also obvious that the language has evolved so 
something that was idiomatic in the 17th century may not make sense now.  

 

The full original text in English is: 

 

Amyntas with his Phyllis fair,

In height of summer's sun,

Graz'd arm in arm their snowy flock;

And scorching heat to shun,

Under a spreading elm sat down,

Where Love's delightments done,

'Down, dillie down,' thus did they sing,

There is no life like ours,

No heav'n on earth to shepherd's cells,

No hell to princely bow'rs.

 

 

The first part is still relatively idiomatic in current English, although we 
can draw a discrete curtain over “love’s delightments” and wonder if there is 
some double entendre implied by “dillie dille down.”   But the last two lines 
make sense to us only if the “to” is replaced with “like”  as Peter suggested.  
The phrase “like to” is familiar to us from poetry but is no longer idiomatic.  
This is confirmed by the sense given to it by a German translation (thank you 
Google) 

 

Amyntas und seine schöne Phyllis hüteten,

als die Sommersonne am höchsten stand,

Arm in Arm ihre schneeweiße Herde,

und um der brütenden Hitze zu entfliehen,

ließen sie sich unter einer Schatten spendenden Ulme nieder.

Dort, nachdem sie die Freuden der Liebe genossen,

„Tra-la-la“, sangen sie:

„Kein Leben könnte schöner sein als das unsrige,

der Himmel auf Erden ist in der Hütte des Schafhirten,

die Hölle in königlichen Gemächern.

 

My German is weak but putting it back into contemporary English: 

 

There is no more beautiful life than ours

Heaven on earth is in a shepherd's hut.

Hell is in royal chambers.  

 

 

The word “bower” is interesting (thank you again Google) and comes from Old 
Norse like a lot of English does.  It originally meant a room or chamber.  It 
retained this sense in the 17th century when it more specifically meant a 
lady’s personal room or chamber in a hall or castle.  I speculate that this 
sense must have been influenced by French “boudoir” which means exactly that 
but comes from “bouder” meaning “to pout”: literally a boudoir is a pouting 
room.  By this time the Norman conquest had imprinted a heavy dose of French 
onto the Norse and Saxon middle English.   The modern meaning of bower is a 
pleasant shady place under trees or vines so Amyntas and Phyllis were enjoying 
their delightments under the elm tree which could be called a bower.   But the 
German translation, appropriately, kept the sense of “chambers.” 

 

So, to summarize: the original English does not quite make sense to a modern 
reader unless he just guesses that “to” means “like.”

 

Jack Aubert

 

 

From: sundial  On Behalf Of Peter Mayer
Sent: Friday, July 7, 2023 4:19 AM
To: sundial@uni-koeln.de; R. Hooijenga 
Subject: Re: Off topic: English text explanation please

 

Dear Rudolf,

I share your interest in 17th century madrigals.  (Although I'm a firm 
non-smoker, one of my favourites has the line "tobacco is like love..."). My 
interpretation is that this is a compressed form of poetical expression. 
Decompressed, I think, it would be: […] thus did they sing: ‘There is no life 
like ours, No heaven on earth [like] to shepherds' cells, no hell [like] to 
princely bowers’.

That is, there is an assumed parallelism with the first phrase.

best wishes,

Peter

On 7/07/2023 7:45:10, R. Hooijenga via sundial wrote:

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Department of Politics & International Relations (POLIR)
School of Social Sciences
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The University of Adelaide, AUSTRALIA 5005
Ph : +61 8 8313 5609
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Re: Off topic: English text explanation please

[Peter Mayer]

Dear Rudolf,

I share your interest in 17th century madrigals.  (Although I'm a firm 
non-smoker, one of my favourites has the line "tobacco is like 
love..."). My interpretation is that this is a compressed form of 
poetical expression. Decompressed, I think, it would be: […] thus did 
they sing: ‘There is no life like ours, No heaven on earth [like] to 
shepherds' cells, no hell [like] to princely bowers’.


That is, there is an assumed parallelism with the first phrase.

best wishes,

Peter

On 7/07/2023 7:45:10, R. Hooijenga via sundial wrote:

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Department of Politics & International Relations (POLIR)
School of Social Sciences
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The University of Adelaide, AUSTRALIA 5005
Ph : +61 8 8313 5609
Fax : +61 8 8313 3443
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RE: Question About Measuring Wall Declination

[Barbara & Carl Sabanski]

You can build one of these.

 

https://www.mysundial.ca/sdu/sdu_wall_declinometer.html

 

 

From: sundial [mailto:sundial-boun...@uni-koeln.de] On Behalf Of Michael 
Ossipoff
Sent: July 1, 2023 1:07 PM
To: Jeffery Brewer; sundial list
Subject: Re: Question About Measuring Wall Declination

 

I realize that you’ve already gotten good answers, but I’d like to say a few 
things too.

…

I’m really late replying, because I’ve been trying to figure out how to word 
answers to a few long assertion-posts from the usual confused self-sure kids at 
a philosophical forum. After this time, I’m going to, one way or another, in 
the forum-options, or my inbox-settings, do a setting that stops 
topic-announcements from those forums from appearing at my inbox.

…

First, are you sure that a nail in the wall is the best way?  It’s very 
unlikely to go in perpendicular to the wall.  Best would be a block or box 
that’s reliably rectangular-prism in shape.  Lacking that, why not use the 
short cardboard tube from inside a bathroom-tissue roll?

…

Assume that the plane of its edge at the ends is perpendicular to its axis & 
cylindrical-surface.

…

Stand it on a flat surface, & use a carpenter’s square, a right-triangle 
drafting square, or a protractor, to mark a vertical line on the tube…or at 
least the two endpoints of a vertical line.

…

At the top end of the line, make a small notch, & let that be the 
shadow-casting point, using the line as the nail.

…

You’ve got the formula for the declination of a vertical wall, in terms of the 
measurements of the shadow of a perpendicular object, but you’re interested in 
the derivation of the solution, & you’ve already gotten good answers about 
that. But I’d like to make a few comments.

…

I’m going to refer to the declining-ness of a declining wall, its distance from 
due-south, as its “facing”, because the word “declination” of course already 
has a meaning in dialing & astronomy—altitude with respect to the 
equatorial-plane.  

…

Referring to the spherical coordinate-system whose equatorial-plane is the 
surface of the declining-wall, I’ll call it the “declining-wall system”.

To refer to the spherical coordinate-system whose equatorial plane is the 
surface of a south-facing wall, I’ll call it the “south-face system”.

…

This is one of those problems in which, it seems to me, the most 
computationally-efficient derivation isn’t the most straightforward, obvious, 
natural  easiest one.  ...where, in particular, the computationally-efficient 
derivation uses plane-trigonometry, & the more straightforward easy natural one 
uses a spherical-coordinate transformation.

…

Formulas for the length & direction of the nail’s shadow, from the Sun’s 
position in the coordinate-system with its equator parallel to the wall, can be 
gotten by coordinate transformations from the Sun’s position in the equatorial 
co-ordinate-system.

…

Determine the Sun’s equatorial-coordinates:

…

The Sun’s hour-angle, its longitude in the equatorial-system, is given by the 
sundial-time (French hours, equal-hours), the True-Solar Time, gotten from the 
clock-time by the usual use of the Equation-of-Time & the longitude correction. 
Hour angle is reckoned clockwise (westward) from the meridian.

…

The Sun’s declination (altitude in the equatorial-system) for a particular day 
can be looked up, & interpolated for a particular hour.

…

It seems to me that the most straightforward solution is to transform the Sun’s 
equatorial coordinates to the south-face system.

…

Then transform the Sun’s south-face coordinates to the declining-wall system.

…

The Sun’s altitude in the declining-wall system gives the length of the shadow, 
Its longitude in the declining-wall system gives the direction of the shadow on 
the wall.

…

You could use the shadow’s length or its direction. The shadow’s length, from 
the Sun’s altitude in the declining-wall system, has a briefer formula, & the 
length of the shadow is easier to measure than its direction.   …& so I’ll 
speak of using the length of the shadow.

…

Resuming: When you’ve transformed the Sun’s south-face coordinates to 
declining-wall coordinates, the resulting formula for the Sun’s altitude in the 
declining-wall system will include a variable consisting of the angle between 
one system’s pole & the other system’s equatorial-plane. (That’s the latitude 
when you’re converting between the horizontal & equatorial systems, & so I call 
it the “latitude” for any coordinate transformation. That’s what I mean by 
“latitude”, in quotes, here)

…

Solve that formula for the “latitude”. Evaluate the “latitude”.  Subtract that 
from 90 degrees, to get the wall’s facing.  …thje amount by which it declines.

…

This assumes that the wall declines by less than 90 degrees.

…

Incidentally, this isn’t the only problem in which coordinate-transformations 
seem more straightforward than the plane-trigonometr

Re: Question About Measuring Wall Declination

[Michael Ossipoff]

I realize that you’ve already gotten good answers, but I’d like to say a
few things too.

…

I’m really late replying, because I’ve been trying to figure out how to
word answers to a few long assertion-posts from the usual confused
self-sure kids at a philosophical forum. After this time, I’m going to, one
way or another, in the forum-options, or my inbox-settings, do a setting
that stops topic-announcements from those forums from appearing at my inbox.

…

First, are you sure that a nail in the wall is the best way?  It’s very
unlikely to go in perpendicular to the wall.  Best would be a block or box
that’s reliably rectangular-prism in shape.  Lacking that, why not use the
short cardboard tube from inside a bathroom-tissue roll?

…

Assume that the plane of its edge at the ends is perpendicular to its axis
& cylindrical-surface.

…

Stand it on a flat surface, & use a carpenter’s square, a right-triangle
drafting square, or a protractor, to mark a vertical line on the tube…or at
least the two endpoints of a vertical line.

…

At the top end of the line, make a small notch, & let that be the
shadow-casting point, using the line as the nail.

…

You’ve got the formula for the declination of a vertical wall, in terms of
the measurements of the shadow of a perpendicular object, but you’re
interested in the derivation of the solution, & you’ve already gotten good
answers about that. But I’d like to make a few comments.

…

I’m going to refer to the declining-ness of a declining wall, its distance
from due-south, as its “facing”, because the word “declination” of course
already has a meaning in dialing & astronomy—altitude with respect to the
equatorial-plane.

…

Referring to the spherical coordinate-system whose equatorial-plane is the
surface of the declining-wall, I’ll call it the “declining-wall system”.

To refer to the spherical coordinate-system whose equatorial plane is the
surface of a south-facing wall, I’ll call it the “south-face system”.

…

This is one of those problems in which, it seems to me, the most
computationally-efficient derivation isn’t the most straightforward,
obvious, natural  easiest one.  ...where, in particular, the
computationally-efficient derivation uses plane-trigonometry, & the more
straightforward easy natural one uses a spherical-coordinate transformation.

…

Formulas for the length & direction of the nail’s shadow, from the Sun’s
position in the coordinate-system with its equator parallel to the wall,
can be gotten by coordinate transformations from the Sun’s position in the
equatorial co-ordinate-system.

…

Determine the Sun’s equatorial-coordinates:

…

The Sun’s hour-angle, its longitude in the equatorial-system, is given by
the sundial-time (French hours, equal-hours), the True-Solar Time, gotten
from the clock-time by the usual use of the Equation-of-Time & the
longitude correction. Hour angle is reckoned clockwise (westward) from the
meridian.

…

The Sun’s declination (altitude in the equatorial-system) for a particular
day can be looked up, & interpolated for a particular hour.

…

It seems to me that the most straightforward solution is to transform the
Sun’s equatorial coordinates to the south-face system.

…

Then transform the Sun’s south-face coordinates to the declining-wall
system.

…

The Sun’s altitude in the declining-wall system gives the length of the
shadow, Its longitude in the declining-wall system gives the direction of
the shadow on the wall.

…

You could use the shadow’s length or its direction. The shadow’s length,
from the Sun’s altitude in the declining-wall system, has a briefer
formula, & the length of the shadow is easier to measure than its direction.
…& so I’ll speak of using the length of the shadow.

…

Resuming: When you’ve transformed the Sun’s south-face coordinates to
declining-wall coordinates, the resulting formula for the Sun’s altitude in
the declining-wall system will include a variable consisting of the angle
between one system’s pole & the other system’s equatorial-plane. (That’s
the latitude when you’re converting between the horizontal & equatorial
systems, & so I call it the “latitude” for any coordinate transformation.
That’s what I mean by “latitude”, in quotes, here)

…

Solve that formula for the “latitude”. Evaluate the “latitude”.  Subtract
that from 90 degrees, to get the wall’s facing.  …thje amount by which it
declines.

…

This assumes that the wall declines by less than 90 degrees.

…

Incidentally, this isn’t the only problem in which
coordinate-transformations seem more straightforward than the
plane-trigonometry solution:

…

I once noticed that a vertical-declining dial can be marked by plane
trigonometry, but spherical coordinate-transformations seem more
straightforward.

…

Likewise, it seems to me that the marking of the declination-lines for a
Horizontal-Dial can be done most computationally-efficiently by plane
trigonometry at the dial.,   …but calculating the Sun’s altitude & azimuth
for each 

Re: Question About Measuring Wall Declination

[Alexei Pace]

Hi Jeffery you are actually calculating the horizontal angle indicated as
'angolo' on the diagram below
ie. deviation of the Sun from the wall under consideration.
Hope this helps,
Alexei


[image: image.png]

On Mon, 26 Jun 2023 at 16:37, Jeffery Brewer 
wrote:

> I'm attempting to measure the declination of a wall using a method
> described on this web page of The Sundial Primer
> https://www.mysundial.ca/tsp/wall_declination.html (also described in
> "Sundials: Their Theory and Construction" by Albert E Waugh Chapter 10).
>
> Referring to Figure 1 of The Sundial Primer reference, "The direction of
> the sun relative to the wall, θ, can be determined as follows: θ = arctan(
> AB / Nail Length)°" If I label the ends of the nail with points C and D
> (see figure below) then the formula can be understood as θ = arctan( AB /
> CD )°
>
> [image: Figure1Modified.jpg]
>
> With my very rudimentary understanding of basic trigonometry, I understand
> how the formula would work for a simple right triangle existing in a single
> plane, but not how it works here. It seems to me that AB lies in an XY
> plane parallel to the wall, but CD lies along the Z axis, perpendicular to
> the XY plane. The shape described by ABCD is a sort of twisted rectangle
> and I don't understand how the formula applies.
>
> I'm almost certainly thinking about this wrong (it feels like an optical
> illusion where I can only see the vase and not the faces).
>
> [image: image.png]
>
> If anyone can help me "see the light" I would appreciate it.
>
> Jeff Brewer
>
>
>
>
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
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Re: DeltaCad has been discontinued

[Simon WS]

I would offer for consideration several options that work well and are easy
to program and use; some are more functional than others. I have tried and
written code for all of them, and I discuss them on my website, as well as
having functioning code for various dial types.

NanoCAD https://nanocad.com/

FreeCAD  https://www.freecad.org/

Powerdraw   http://www.powerdraw.software.informer.com

OpenSCAD http://www.openscad.org/

Check  http://www.illustratingshadows.com

I have a page covering each of the above as well as other systems.

Also look at my free book Programming Shadows which has detailed code and
explanations for each system.

http://illustratingshadows.com/programmingShadows.pdf

Simon Wheaton-Smith

On Thu, May 4, 2023 at 11:50 PM Alexei Pace  wrote:

> Good morning Dan-George, as an alternative one may wish to try
> https://www.qcad.org/en perhaps.
>
> Alexei
>
> On Fri, 5 May 2023 at 07:34, Dan-George Uza 
> wrote:
>
>> Hello,
>>
>> I've just found out that DeltaCad has been discontinued so you won't be
>> able to download the demo any longer. I find this very sad, it was a very
>> simple CAD software with many useful sundial macros available. However, it
>> seems that you will still be able to download your purchased copy.
>>
>> Best wishes,
>>
>> --
>> Dan-George Uza
>> ---
>> https://lists.uni-koeln.de/mailman/listinfo/sundial
>>
>> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>

-- 
Simon Wheaton-Smith
www.illustratingshadows.com
Phoenix, AZ
W 112.1, N 33.5
---
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Re: DeltaCad has been discontinued

[Simon [illustratingshadows via sundial]

Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die
eigentliche Nachricht steht dadurch in einem Anhang.

This message was wrapped to be DMARC compliant. The actual message
text is therefore in an attachment.--- Begin Message ---
I would offer for consideration several options that work well and are easy to 
program and use; some are more functional than others. I have tried and written 
code for all of them, and I discuss them on my website, as well as having 
functioning code for various dial types.
NanoCAD     https://nanocad.com/
FreeCAD      https://www.freecad.org/
Powerdraw   http://www.powerdraw.software.informer.com
OpenSCAD http://www.openscad.org/
Check          http://www.illustratingshadows.com    
I have a page covering each of the above as well as other systems. 
Also look at my free book Programming Shadows which has detailed code and 
explanations for each system.
                    http://illustratingshadows.com/programmingShadows.pdf
Simon Wheaton-Smith
 

On Thursday, May 4, 2023 at 11:50:46 PM MDT, Alexei Pace 
 wrote:  
 
 Good morning Dan-George, as an alternative one may wish to try 
https://www.qcad.org/en perhaps.
Alexei
On Fri, 5 May 2023 at 07:34, Dan-George Uza  wrote:

Hello,

I've just found out that DeltaCad has been discontinued so you won't be able to 
download the demo any longer. I find this very sad, it was a very simple CAD 
software with many useful sundial macros available. However, it seems that you 
will still be able to download your purchased copy.
Best wishes,
-- 
Dan-George Uza---
https://lists.uni-koeln.de/mailman/listinfo/sundial


---
https://lists.uni-koeln.de/mailman/listinfo/sundial

  --- End Message ---
---
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Re: DeltaCad has been discontinued

[Alexei Pace]

Good morning Dan-George, as an alternative one may wish to try
https://www.qcad.org/en perhaps.

Alexei

On Fri, 5 May 2023 at 07:34, Dan-George Uza  wrote:

> Hello,
>
> I've just found out that DeltaCad has been discontinued so you won't be
> able to download the demo any longer. I find this very sad, it was a very
> simple CAD software with many useful sundial macros available. However, it
> seems that you will still be able to download your purchased copy.
>
> Best wishes,
>
> --
> Dan-George Uza
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: analemmatic sundial

[ro...@torrenti.net]

Hi Donald,

You may want to consider CADSOL online, an online software (no need to download 
anything) developed by Jean-Luc Astre (instructions in English and free of use).
https://cadsol.web-pages.fr/CadsolOnLine/sources/colmod2023-04-25.html

It can be referred to for different types of sundials, including analemmatic 
ones.

Kind regards
Roger


De : sundial  de la part de Kurt Niel 

Date : lundi, 1 mai 2023 à 08:00
À : Donald Christensen 
Cc : Sundial mailing list 
Objet : Re: analemmatic sundial
Hi Donald,

www.helson.at<http://www.helson.at>

A very supportive SW with a lot of different types of sundials!

Kurt

Donald Christensen 
mailto:dchristensen...@gmail.com>> schrieb am Mo., 
1. Mai 2023, 07:44:

I’m looking for a program to calculate an analemmatic sundial. Can anybody help?

Cheers
Donald Christensen
0467 332 227

If you focus on what you lack, you'll lose what you have. If you focus on what 
you have, you gain what you lack.
---
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---
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Re: analemmatic sundial

[keith . christian]

What happened to your "Sundials for Learning" business (a few years 
back) - when you were offering plans for Analemmatic Sundials to schools 
?


It seems to me, that you already had the appropriate software.

Keith Christian.

On 2023-05-01 06:44, Donald Christensen wrote:

I'm looking for a program to calculate an analemmatic sundial. Can 
anybody help?


Cheers
Donald Christensen
0467 332 227

If you focus on what you lack, you'll lose what you have. If you focus 
on what you have, you gain what you lack.

---
https://lists.uni-koeln.de/mailman/listinfo/sundial---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: analemmatic sundial

[Donald Christensen]

Thank you. I forgot to specify that it needs to be able to run on osx

On Mon, May 1, 2023 at 4:00 PM Kurt Niel  wrote:

> Hi Donald,
>
> www.helson.at
>
> A very supportive SW with a lot of different types of sundials!
>
> Kurt
>
> Donald Christensen  schrieb am Mo., 1. Mai
> 2023, 07:44:
>
>> I’m looking for a program to calculate an analemmatic sundial. Can
>> anybody help?
>>
>> Cheers
>> Donald Christensen
>> 0467 332 227
>>
>> If you focus on what you lack, you'll lose what you have. If you focus on
>> what you have, you gain what you lack.
>> ---
>> https://lists.uni-koeln.de/mailman/listinfo/sundial
>>
>>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: analemmatic sundial

[Kurt Niel]

Hi Donald,

www.helson.at

A very supportive SW with a lot of different types of sundials!

Kurt

Donald Christensen  schrieb am Mo., 1. Mai 2023,
07:44:

> I’m looking for a program to calculate an analemmatic sundial. Can anybody
> help?
>
> Cheers
> Donald Christensen
> 0467 332 227
>
> If you focus on what you lack, you'll lose what you have. If you focus on
> what you have, you gain what you lack.
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Seeking information on "F.G. Cheney"

[Steve Lelievre]

Hi,

Thanks!

Steve

On 2023-04-20 1:36 a.m., Hendrik Desmet wrote:

I found this:
"(...) Eight years later, Frank purchased *Cheney Foundry*, a small 
company in Minneapolis that poured aluminum and brass, from its 
retiring owner in 1963. Frank managed the foundry, and Lois managed 
the office.(...)

See https://carleyfoundry.com/about/history

Kind regards
Hendrik

---
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Re: Seeking information on "F.G. Cheney"

[Hendrik Desmet]

I found this:
"(...) Eight years later, Frank purchased *Cheney Foundry*, a small company in 
Minneapolis that poured aluminum and brass, from its retiring owner in 1963. 
Frank managed the foundry, and Lois managed the office.(...)
See https://carleyfoundry.com/about/history

Kind regards
Hendrik

Op do 20 apr 2023, om 0:46 schreef Steve Lelievre:
> Hello,
>
> My question is mostly for dialists in the USA - can anyone tell me if 
> there was a dial maker called Cheney (or a foundry that had dials in 
> their product line) active in the early 1960s, possibly in the San 
> Francisco area?
>
> I'm trying to trace the origins of a 1961 dial that has "F.G.Cheney" 
> cast into the underside.
>
> Through Google I only found two businesses named F.G.Cheney. One is a 
> quarry in Michigan and another that's a pharmacy in Ohio.
>
> Thanks,
>
> Steve
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Frank Cheney

[Steve Lelievre]

Excellent!

That'll be him.

Thanks very much,

Steve


On 2023-04-19 3:55 p.m., Patrick Vyvyan wrote:
This quote is from the North American Sundial Society description of a 
sundial in the Old Rose Garden of the Botanical Garden

University of California at Berkeley

"The armillary dial is made of red bronze and rests on a quarried 
stone pedestal. The equatorial ring includes hour lines with 15-minute 
marks and Roman numerals. It was created by Frank Cheney, a UC 
Berkeley graduate, Class of 1941, and later donated to the Garden by 
his family. Mr. Cheney was a civil engineer who developed a hobby of 
building sundials"


https://sundials.org/index.php/component/sundials/onedial/612

Probably the same person?

Best wishes,
Patrick Vyvyan

 
	Libre de virus.www.avast.com 
 




---
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---
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Re: Adjusting dial to new location

[Michael Ossipoff]

I mentioned several alignments, the correction of any one of which could be
used to determine how much the dial-plate should be rotated in its own
plane (either before or after the tip).

Most recently I suggested the altitude of the pointing-direction of the
style.

But it seems to me that it would be easier to correct the
pointing-direction of the noon-line to the hour-angle equal to 180 degrees
+ the westward longitude-offset (the amount by which you want the LTST o a
longitude west of yours…& of course negative if you want it for a longitude
east of yours). In my example, the longitude-offset way7 degrees.

That correction gives a simpler expression for the necessary dial-plate
rotation in its own plane. (…which can be done before or after the tip).

On Tue, Apr 11, 2023 at 08:52 Michael Ossipoff 
wrote:

> I retract the addendum. I wrote it with the notion that the noon-line
> should be under the style.   …as if the dial were intended to read for its
> own longitude.
>
> So, sorry—disregard the addendum (…as you probably already have).
>
> The dial-plate’s rotation in its own plane should be to correct the
> style’s pointing-direction (in altitude or azimuth), as I originally said &
> described.
>
> Correcting its altitude would give an easier equation-solution.
>
>
>
> On Sat, Apr 8, 2023 at 21:25 Michael Ossipoff 
> wrote:
>
>> Addendum:
>>
>> …
>>
>> Instead of finding the dial-plate rotation in its own plane that corrects
>> the style’s pointing-direction, it might be easier to, instead, find the
>> dial-plate rotation in its own plane that puts the dial’s noon-line in the
>> meridianal-plane….i.e. gives that noon-line an azimuth of zero.
>>
>
---
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Re: Adjusting dial to new location

[Michael Ossipoff]

I retract the addendum. I wrote it with the notion that the noon-line
should be under the style.   …as if the dial were intended to read for its
own longitude.

So, sorry—disregard the addendum (…as you probably already have).

The dial-plate’s rotation in its own plane should be to correct the style’s
pointing-direction (in altitude or azimuth), as I originally said &
described.

Correcting its altitude would give an easier equation-solution.



On Sat, Apr 8, 2023 at 21:25 Michael Ossipoff 
wrote:

> Addendum:
>
> …
>
> Instead of finding the dial-plate rotation in its own plane that corrects
> the style’s pointing-direction, it might be easier to, instead, find the
> dial-plate rotation in its own plane that puts the dial’s noon-line in the
> meridianal-plane….i.e. gives that noon-line an azimuth of zero.
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[Michael Ossipoff]

For complete generality:

If your sundial was made for a latitude greater then yours by an amount
called “DeltaLat” (which could be positive or negative), & if you want the
dial to give LTST for a longitude 7 degrees west of yours (maybe because
that’s your standard-meridian), then:

After the tip, the initially-top-point of the sphere with a great-circle
coinciding with the circumference of your circular dial-plate will have
equatorial-coordinates of:

(Lat+DeltaLat, 7).

After that, it’s exactly as I said.





On Sun, Apr 9, 2023 at 14:09 Steve Lelievre 
wrote:

>
> On 2023-04-08 8:52 p.m., Michael Ossipoff wrote:
>
> I know you said you wanted a link, not instructions, but people have been
> suggesting how to achieve dial-autocorrection to Local True Solar Time
> (LTST) at the standard-meridian, instead of one’s own meridian. So I felt
> that it would be justified to comment about it.
>
> Michael,
>
> To me, your case seems to be a specific instance that is covered by the
> general case - have I missed something?
>
> As things stand, I think I know the math involved because I have from the
> article by Fred Sawyer that I mentioned in a previous email. It describes
> the solution for the general case - we start with a dial at some latitude
> and longitude that shows the solar time at some other longitude, which may
> or may not be zero offset. We want to move it to a new latitude and
> longitude and to show the solar time at some new 'other' longitude, which
> may or may not have zero offset from the new location. As well, the article
> by Fabio Savian, mentioned in his post, also discusses dial relocation.
> (BTW, for NASS members, Fabio only mentioned his article in its Italian
> version, but as well he kindly provided an English equivalent which was
> included in the most recent issue of the Compendium)
> Everyone,
>
> Since I'm writing this post, I'll take the opportunity to mention that I
> have made a couple of small adjustments to my online wedge calculator,
> gnomoni.ca/wedge . My thanks go to Roderick Wall for helping me make it
> better for the southern hemisphere. Please let me know if you spot any
> issues.
>
>
> Steve
>
>
>
>
---
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Re: Adjusting dial to new location

[Michael Ossipoff]

Yes, I spoke of a special-case in which you’re 7 degrees east of your
standard-meridian. …for a concrete example. But the rest of what I said was
for the general-case in which you want the dial to read in the LTST at your
standard-meridian.

But yes, I didn’t speak of when the dial is made for a different latitude
*and* you want standard-meridian LTST.

I thought that it was just about getting the standard- meridian LTST.
 …something I wouldn’t do anyway.

On Sun, Apr 9, 2023 at 14:09 Steve Lelievre 
wrote:

>
> On 2023-04-08 8:52 p.m., Michael Ossipoff wrote:
>
> I know you said you wanted a link, not instructions, but people have been
> suggesting how to achieve dial-autocorrection to Local True Solar Time
> (LTST) at the standard-meridian, instead of one’s own meridian. So I felt
> that it would be justified to comment about it.
>
> Michael,
>
> To me, your case seems to be a specific instance that is covered by the
> general case - have I missed something?
>
> As things stand, I think I know the math involved because I have from the
> article by Fred Sawyer that I mentioned in a previous email. It describes
> the solution for the general case - we start with a dial at some latitude
> and longitude that shows the solar time at some other longitude, which may
> or may not be zero offset. We want to move it to a new latitude and
> longitude and to show the solar time at some new 'other' longitude, which
> may or may not have zero offset from the new location. As well, the article
> by Fabio Savian, mentioned in his post, also discusses dial relocation.
> (BTW, for NASS members, Fabio only mentioned his article in its Italian
> version, but as well he kindly provided an English equivalent which was
> included in the most recent issue of the Compendium)
> Everyone,
>
> Since I'm writing this post, I'll take the opportunity to mention that I
> have made a couple of small adjustments to my online wedge calculator,
> gnomoni.ca/wedge . My thanks go to Roderick Wall for helping me make it
> better for the southern hemisphere. Please let me know if you spot any
> issues.
>
>
> Steve
>
>
>
>
---
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Re: Adjusting dial to new location

[Steve Lelievre]

On 2023-04-08 8:52 p.m., Michael Ossipoff wrote:


I know you said you wanted a link, not instructions, but people have 
been suggesting how to achieve dial-autocorrection to Local True Solar 
Time (LTST) at the standard-meridian, instead of one’s own meridian. 
So I felt that it would be justified to comment about it.



Michael,

To me, your case seems to be a specific instance that is covered by the 
general case - have I missed something?


As things stand, I think I know the math involved because I have from 
the article by Fred Sawyer that I mentioned in a previous email. It 
describes the solution for the general case - we start with a dial at 
some latitude and longitude that shows the solar time at some other 
longitude, which may or may not be zero offset. We want to move it to a 
new latitude and longitude and to show the solar time at some new 
'other' longitude, which may or may not have zero offset from the new 
location. As well, the article by Fabio Savian, mentioned in his post, 
also discusses dial relocation. (BTW, for NASS members, Fabio only 
mentioned his article in its Italian version, but as well he kindly 
provided an English equivalent which was included in the most recent 
issue of the Compendium)


Everyone,

Since I'm writing this post, I'll take the opportunity to mention that I 
have made a couple of small adjustments to my online wedge calculator, 
gnomoni.ca/wedge . My thanks go to Roderick Wall for helping me make it 
better for the southern hemisphere. Please let me know if you spot any 
issues.


Steve


---
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Re: Adjusting dial to new location

[Michael Ossipoff]

Addendum:

…

Instead of finding the dial-plate rotation in its own plane that corrects
the style’s pointing-direction, it might be easier to, instead, find the
dial-plate rotation in its own plane that puts the dial’s noon-line in the
meridianal-plane….i.e. gives that noon-line an azimuth of zero.
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[Michael Ossipoff]

Steve—

…

I know you said you wanted a link, not instructions, but people have been
suggesting how to achieve dial-autocorrection to Local True Solar Time
(LTST) at the standard-meridian, instead of one’s own meridian. So I felt
that it would be justified to comment about it.

…

…even though that autocorrection wouldn’t bring any convenience for the
user, who’d still need a correction (for Eqt), & even though it would
create an inconvenience for anyone who wanted genuinely local LTST, because
they’d have to uncorrect the longitude-correction.

…

First I suggested solution of 3 simultaneous nonlinear equations, written
via coordinate-transformation formulas, with three unknown variables:
Initial horizontal dial-plate rotation about the vertical axis through its
center, the place on the dial-plate circumference for placing the wedge, &
the amount to tip the plate with that wedge.

…

…in order to get the style pointed at the celestial-pole, with the
noon-line in the meridianal-plane.  3 equations in 3 unknowns.

…

Undeniably that would solve the problem, but 3 nonlinear equations would be
a bit of work.  That work is unnecessary, because it can be solved
analytically.

…

I described how one could find how to tip the dial-plate:

…

1) The point at the top of the sphere having a great-circle that coincides
with the circumference of the dial-plate, has, in the
equatorial-coordinate-system,  a declination equal to the latitude of the
dial. It has an hour-angle (equatorial longitude) of zero.

…

2) Say you’re 7 degrees east of your standard meridian. Rotating the dial 7
degrees westward about the polar axis, the axis of the equatorial-system,
changes the top-point’s equatorial coordinates to (Lat, 7).

…

3) Transform those new equatorial coordinates to the horizontal coordinate
system, to get the altitude & azimuth of the top-point.

…

4) Place the wedge at the edge of the circular dial-plate 180 degrees from
the calculated azimuth of the top point.  Tip the dial-plate up, there, by
an angle equal to the complement of the calculated altitude of the
top-point.

…

Now the dial-plate is tipped as it would be if the dial had been rotated 7
degrees westward in equatorial-longitude, hour-angle,  about the polar-axis.
But the dial’s noon-line might not be in the meridianal-plane.

…

One way to fix that:

…

5) Rotate the dial-plate in the plane of the dial-face, until the dial
reads the correct LTST at the standard-meridian.

…

That would require carefully marking where the edge of the dial place is,
at several circumference-positions on the table-surfa ce, marking where the
wedge with respect to dial & table-surface, & marking where the dial-plate
touches the wedge.

…

Then lift the dial-plate a bit off the wedge & rotate the dial-plate in the
plane of its dial-surface, & set it back down, making sure that the
dial-plate & wedge are at their original marks.

…

Do that till the dial reads the LTST at the standard-meridian.

…

That dial-rotation sounds laborious & awkward, doing it after the tipping,
with all the position marking & keeping.   …especially with the wedge under
the dial-plate.

…

Another way:

…

6) Before the tipping, the style is pointing at the celestial-pole.
Transform that position to the get the pole’s pre-tip coordinates in the
coordinate system whose axis is a horizontal line perpendicular to the
direction in which the direction in which the dial is going to be tipped.  Now
add the complement of the calculated top-point-altitude to the longitude in
that system with the horizontal axis. That gives the style’s
pointing-direction’s new longitude in the system with the horizontal  tip-axis.
So now you have both of its new coordinates in that system.

…

7) Transform that position to either the horizontal (altazimuth)
coordinate-stem, to get the altitude & azimuth of the style’s new
pointing-direction…or instead to the equatorial-system to get the style’s
pointing-direction, as declination & hour-angle in the equatorial-system.

…

8) That tells you how much the style’s pointing-direction is off, in terms
of its altitude, or its azimuth, or its declination.   …whichever of those
you want to use.  Its azimuth should of course be zero. Its altitude should
of course equal your latitude, & its declination of course should be 90
degrees. The altitude is probably not a good choice to use, because it
changes more slowly with change in the dial plate rotation.  I’d probably
use the declination, because its formula is simpler than that of the
azimuth.

…

9) So, find out how much thequantity for the style’s pointing-direction
that you’re using, say the declination,  needs to change, to put it where
it should be. Another coordinate-transformation will tell you how much the
dial-plate would have to rotate in the plane of the dial-face, to achieve
that.  That’s the desired dial-plate-rotation.

…

10) So, before tipping,  you rotate the dial-plate in its own plane, by
that amount, before you 

Re: Adjusting dial to new location

[Michael Ossipoff]

 Contrary to what I suggested yesterday, the adjustment of a sundial to
give LTST at the standard-meridian doesn’t require solution of a system of
equations. It’s a straightforward coordinate-transformation:

…

Say the dial-plate is circular. For a sphere that circumscribes that
dial-plate, the equatorial-coordinates on the sphere, of a point at the top
of that sphere, are (Lat, 0).

...

…where Lat is the latitude of the dial’s location, & 0 is defined as the
longitude of the topmost meridian in the equatorial-system.

…

Now, say your location is 7 degrees east of your standard meridian. You
want to change the equatorial-coordinates of that top-point to (Lat, 7).

...

(…because let’s say that hour-angle (equatorial-longitude) is measured
clockwise (westward) from the NS meridian, as it normally is.)

…

That’s the top-points coordinates in the equatorial system when the sphere
has been rotated 7 degrees about its polar-axis, toward the
standard-meridian.

...

Now transform the top-point’s coordinates (Lat, 7) to the horizontal
coordinate-system.

…

That gives you the azimuth & altitude of the top-point, as seen from the
center of the sphere.

…

The dial-edge is a great circle on the sphere, all of which is 90 degrees
away from the former top-point.

…

The place on the dial-plate that should be raised is the place 180 degrees
from the top-point’s azimuth.

…
Raise that point by an angle equal to the complement of the altitude of the
top-point

On Sun, Mar 26, 2023 at 5:30 PM Steve Lelievre <
steve.lelievre.can...@gmail.com> wrote:

> Hi,
>
> Can anyone point me to an existing online calculator for making a wedge
> to adjust a horizontal dial to a new latitude and longitude?
>
> I am not asking for an explanation of how to do the calculation; I just
> want to be able to point people to a calculator that has already been
> proved on the internet. It should use the original location (latitude
> and longitude) and the new location to calculate the angle of slope of
> the wedge and the required rotation from the meridian.
>
> Many thanks,
>
> Steve
>
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[Michael Ossipoff]

[quote]

Assuming that a dial should read only local solar time is a rather limited
view.

[/quote]

…

:-)  What?

…

So, an expressed preference is a “limited view”?  :-)

…

LTST stands for Local-True-Solar-Time.

…

A dial that reads in LTST at your latitude *at your standard
meridian*…instead of *where the sundial is*, makes no sense.

…

It doesn’t make it any easier for viewers to obtain clock-time from the
dial.  That’s because, if the dial reads in your LTST, where the dial is,
then, when making the correction-table, the longitude-correction-constant
can just be added to every EqT entry, resulting in a combined-corrections
table.

…

Then, the user’s task, for converting from dial-time to standard time, is
exactly the same:  Add a correction from a correction-table.

…

In other words, making dial read in LTST at your standard-meridian, instead
of where the dial is, doesn’t make it any easier for the viewer to get
clock-time from the dial.

…

But what it DOES accomplish is that it makes it necessary to apply a
correction in order to get LTST (where you are) from the dial.

…

[quote]

While it might be of interest to the dial purist

[/quote]

…

LTST, Sundial-Time is the time-of-day that standard-time is based on &
approximated.  …but LTST is the real-thing.  A dial that reads in LTST is
telling you the actual time-of-day by the Sun.

…

For appointments, & catching a scheduled bus, train or flight, clock-time
is what matters. For the Sun’s time-of-day, LTST is what it’s about, & what
standard-time is merely a rough approximation of.

…

Yes, other kinds of hours have been used. Temporary Hours must have been
useful if you had some task that needed daylight, &, to evaluate your
progress in that task, it was helpful to know what fraction of the day has
elapsed. You’ve plowed ¾ of the field, & about ¾ of the day has elapsed, &
so you know that your progress is good.

…

Myself, I personally don’t like Temporary Hours, because I don’t want to be
told what fraction of the day has elapsed, because it sounds like negative
news. It seems to me that it emphasizes a negative interpretation of the
time-of-day.  Just my impression.

…

Co-Italian Hours can be very relevant, however, when it tells you how many
hours of daylight remain.  Better yet, I’d prefer being told how many hours
remained until the end of evening Civil-Twilight.

…

My next sundials will give French Hours (equal 15-degree hours) &
Co-Italian Hours (but hours till the end of evening Civil-Twilight instead
of Sunset).

…

Also, my next sundials will have declination-lines for the Solar
ecliptic-months (Aries-Pisces)., marked with the old symbols for those
ecliptic-months.  I’ll also add declination-lines for some days during the
waxing half of the year, when the Solar-Declination has gone significant
fractions of the way from its Winter-Solstice value to its Summer-Solstice
value.   …&, additionally, declination-lines for the ancient Celtic
cross-quarter seasonal-holidays.

…

[quote]

it is not particularly useful to the general population

[/quote]

…

News-flash:  People nowadays take pleasure from, & admire sundials for
reasons other than practical-need.

…

Sundials are liked & looked-at & read because of their beauty & their
natural significance, directly showing nature’s time, the Sun’s own time,
based on where the Sun actually is.   …not clock-time.

…

As I mentioned, LTST is what standard-time is based on & approximates…but
LTST is the real-thing. The genuine natural Solar time-of-day…the kind
expressed in equal 15-degree hours.

…

Clock time can indeed be important, when you have an appointment, meeting
job deadline, or must catch a bus, train or plane, etc.  That just isn’t
part of what people like about sundials.

…

As I’ve mentioned, I used to use & carry a tablet-dial, when reliable
accurate watches were expensive. It had a combined
longitude-correction-constant + Eqt, on the top of the closed tablet. One
single correction-table for the combined correction.

…

[quote]

 and often requires a lot of explanation.

[/quote]

…

How hard is it to tell someone that the Sundial tells the time based on
where the Sun is, as opposed to clock-time, which has less relation to the
Sun’s time.

…

A Sundial that reads directly in the LTST where you are doesn’t need any
correction for that.

…

Getting clock-time from a sundial that reads directly in the LTST at your
standard-meridian needs the EqT correction to be applied, to get
standard-time.   …but also needs a correction to be applied to get your
LTST where the dial is.

…

So which is really simpler?.

…

[quote]

And it makes us seem like an eccentric clique.

[/quote]

…

People don’t come over  & look at a Sundial because they want clock-time
from it. They like its beauty & its Solar nature significance, when it
directly tells them the time based on where the Sun is, Sun’s time,
nature’s time.

…

[quote]

The dial produces a shadow. The hour lines and other indications are

Re: Adjusting dial to new location

[Michael Ossipoff]

By “auto-correction”, I refer modification of the dial, so that it will
directly read Local-True-Solar-Time (LTST) at your latitude at your
standard-meridian instead of where the dial is.

…

Auto-correcting for longitude by rotating & tipping the dial is a
“retrofit” longitude auto-correction, as opposed to initially incorporating
that auto-correction in the marking of the dial.

…

(As I said, I have no idea why anyone would want longitude-auto-correction,
to make the dial read the Local-True-Solar-Time (LTST) at your latitude at
your timezone’s standard-meridian (instead of where the dial is). Because
the longitude-correction could be achieved by merely adding the
longitude-correction constant to each EqT entry on the correction-plaque,
the auto-correction doesn’t avoid any table-consulting & correction work
needed by the dial-user who wants standard-time.  All it accomplishes is to
make LTST determination require a correction too.)

…

As has already been pointed out twice, only one wedge is needed.

…

The longitude-correction could be achieved by, first, an initial rotation
about the vertical axis, & then a rotation about some particular horizontal
axis.

…

Three variables:

…

1. The amount & direction of initial rotation, about the vertical-axis,
away from the NS alignment of the gnomon.

…

2. The place on the circular-dial-plate’s circumference at which the wedge
is applied.

…

3. The amount by which the dial-plate is tipped by that wedge.

…

There are three desiderata:

…

1. The style is in the meridianal-plane, with its higher end poleward.

…

2.The Style is tipped above the horizontal by an angle equal to the
latitude.

…

3. The dial has been rotated about the style so as to have the orientation
of flat ground at your standard-parallel.at your latitude. (i.e. rotated in
the direction of your standard meridian, by the number of degrees by which
that meridian differs from yours.)

…

Those 3 desiderata give 3 equations in 3 unknowns. The 3 variable are the
unknowns.

…

The equations are spherical co-ordinate-transformation formulas. The 3
equation are statements, in terms of those formulas, that the 3 desiderata
are achieved.

…

The 3 nonlinear equations in 3 unknowns can be numerically-solved by the
Newton-Raphson method,  In fact according to some authors, Newton-Raphson
is the only method available for a system  of nonlinear equations.

…

You speak of rotation about 3 axes. …2 of them by wedges?  (…because you’ve
suggested 2 wedges.).

,,,

When the 1st wedge is put in at (say) the dial-plate’s north edge, the dial
plate is supported by, & stably balanced on, the wedge at the dial-plate’s
north edge, & the dial edge opposite the wedge, at the south edge of the
dial-plate. That means that the whole dial-plate & all of its periphery
(except its south-point) are above the horizontal table-surface on which
the dial was resting.

…

Now, when you put a 2nd wedge in at (say) the dial-plate’s east edge, &
push it in till it contacts the raised dial-edge, & then & start rotating
the dial-plate with it, about what axis are you rotating the
dial-plate?  You’re
rotating it about the line drawn between the point at the dial-plate’s
south edge, where the dial-plate rests on its horizontal table, & some
point on the west edge of the wedge at the north end of the dial.

…

That isn’t a horizontal axis.

…

I guess you could do it that way, but it sounds like more work than the use
of just one wedge.

…

As I said, you only need one wedge.

…

Your other suggestion expressed after that is unclear.

On Tue, Apr 4, 2023 at 7:38 PM  wrote:

> Depending on your choice of rotation axes, only two rotations are needed,
> one for the elevation of the pole and one around the gnomon for longitude
> correction. These are the two that correspond to the actual changes needed.
>
> If you are using the three orthogonal x, y, and z axes, then three
> rotations are needed. And they can tell you how to make the wedge.
>
> Another three rotation procedure that might be easier to understand but
> may not tell you how to make the wedge is this. Rotate about a horizontal
> axis until the gnomon is vertical. Now rotate around the vertical axis to
> include the longitude correction. Then rotate around a horizontal axis to
> put the gnomon in the correct new location. I would do this in a computer
> graphics situation because it only requires the old and new position values.
> ---
>
>
>
> On 2023-04-04 15:54, Steve Lelievre wrote:
>
>
> At a new location, a dial must end up with the style parallel to the polar
> axis - but how do you achieve that using a wedge? Assuming you start with
> the dial at the new location on a horizontal surface with the sub-stile
> line on the local meridian, the required sequence is to rotate it about the
> local vertical, then about an east-west line, and then about the vertical
> again. Perhaps this helps visualize it... https://youtu.be/mtEgSXJPXSw
>
> The wedge achieves the same thing 

Re: Adjusting dial to new location

[koolish]

Depending on your choice of rotation axes, only two rotations are
needed, one for the elevation of the pole and one around the gnomon for
longitude correction. These are the two that correspond to the actual
changes needed. 


If you are using the three orthogonal x, y, and z axes, then three
rotations are needed. And they can tell you how to make the wedge. 


Another three rotation procedure that might be easier to understand but
may not tell you how to make the wedge is this. Rotate about a
horizontal axis until the gnomon is vertical. Now rotate around the
vertical axis to include the longitude correction. Then rotate around a
horizontal axis to put the gnomon in the correct new location. I would
do this in a computer graphics situation because it only requires the
old and new position values.

---

On 2023-04-04 15:54, Steve Lelievre wrote:

At a new location, a dial must end up with the style parallel to the polar axis - but how do you achieve that using a wedge? Assuming you start with the dial at the new location on a horizontal surface with the sub-stile line on the local meridian, the required sequence is to rotate it about the local vertical, then about an east-west line, and then about the vertical again. Perhaps this helps visualize it... https://youtu.be/mtEgSXJPXSw 

The wedge achieves the same thing because the twisting of the dial on the wedge face corresponds to the first rotation about a vertical, it's tip angle corresponds to the east-west rotation, and the turning of the wedge corresponds to the second rotation about the vertical. 

Steve 

On 2023-04-04 11:59 a.m., Rod Wall wrote: 


As Michael indicated in his email below: Rotating the whole dial around the 
polar axis is the correct way. to adjust a local solar time dial to a different 
longitude


---
https://lists.uni-koeln.de/mailman/listinfo/sundial---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[koolish]

Assuming that a dial should read only local solar time is a rather
limited view. While it might be of interest to the dial purist, it is
not particularly useful to the general population and often requires a
lot of explanation. And it makes us seem like an eccentric clique. The
dial produces a shadow. The hour lines and other indications are
strictly our interpretation and a particular one should not be forced on
everybody else.

---

On 2023-04-04 13:05, Michael Ossipoff wrote:

On Tue, Apr 4, 2023 at 08:45  wrote: 

Rotating the dial plate around a vertical axis is wrong because the hours lines are not at constant angles. 

Rotating the whole dial around the polar axis is the correct way to adjust a local solar time dial to a different longitude, the time zone center, for example. 


Having a dial show the time in a different location is strictly a creative 
choice.

---

Rotating the dial about the vertical axis & then doing the non-meridian Al 
tipping, in the right combination, is how you get the result that the dial is 
oriented (still in the meridianal-plane) to give Local True Solar Time at your 
standard meridian.


I don't know why anyone would want to do that, unless it's important to keep using an old EqT plaque. 

On 2023-04-04 08:44, Jack Aubert via sundial wrote: 
Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die

eigentliche Nachricht steht dadurch in einem Anhang.

This message was wrapped to be DMARC compliant. The actual message
text is therefore in an attachment. 
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---
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Re: Adjusting dial to new location

[Steve Lelievre]

At a new location, a dial must end up with the style parallel to the 
polar axis - but how do you achieve that using a wedge? Assuming you 
start with the dial at the new location on a horizontal surface with the 
sub-stile line on the local meridian, the required sequence is to rotate 
it about the local vertical, then about an east-west line, and then 
about the vertical again. Perhaps this helps visualize it... 
https://youtu.be/mtEgSXJPXSw


The wedge achieves the same thing because the twisting of the dial on 
the wedge face corresponds to the first rotation about a vertical, it's 
tip angle corresponds to the east-west rotation, and the turning of the 
wedge corresponds to the second rotation about the vertical.


Steve


On 2023-04-04 11:59 a.m., Rod Wall wrote:


As Michael indicated in his email below: *Rotating the whole dial 
around the polar axis is the correct way. *to adjust a local solar 
time dial to a different longitude


---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[Michael Ossipoff]

The public stationary sundial in my town is mounted normally for Local True
Solar Time. It’s correction-plaque gives un-adjusted EqT, with an
instruction to add a certain number of minutes for the longitude-correction.

On Sun, Apr 2, 2023 at 17:26 Steve Lelievre 
wrote:

> You don’t need two wedges, you just skew the positioning to do both
> adjustments in one.
>
> If you have The Compendium vol 7 issue 1, take a look at the articles by
> Fred Sawyer and Bill Gottesman.
>
> Steve
>
> On Sun, Apr 2, 2023 at 17:20, Rod Wall  wrote:
>
>> Hi Jack and Steve,
>>
>> To implement what Jack has indicated. You could have two wedges one on
>> top of each other. One for Latitude correction and one for Longitude
>> correction.
>>
>> You could also just use a Longitude correction wedge if you only wanted
>> to correct for Longitude.
>>
>> When writing instructions. Please also include people who live in the
>> southern hemisphere, we do also have sundials.
>>
>> Do I have this correct?
>>
>> Roderick.
>>
>> On 3/04/2023 9:24 am, Steve Lelievre wrote:
>>
>> Jack,
>>
>> Try out my calculator! You can specify a time zone meridian for the dial
>> at its original location, or at its new location, or both. If there is an
>> effective longitude change, it'll tell you how to position (twist) the dial
>> on the wedge and how to orient the wedge itself, turning it away (rotating
>> it ) from the meridian line.
>>
>> Steve
>>
>>
>> On 2023-04-02 3:59 p.m., Jack Aubert wrote:
>>
>> I thought about this briefly.  I had always thought that the purpose of
>> the shim or wedge adjustment was to tip the dial north or south so that
>> dial is at the latitude it was originally designed for.  If the original
>> dial has a built-in longitude correction, that could also be factored into
>> a wedge which would have both a north-south and east-west axis.  But a
>> wedge would not work if it moved the gnomon out of alignment with the with
>> the rotation of the earth (or the celestial sphere).  I think a
>> longitudinal adjustment would only work if he original dial had a time-zone
>> offset included by rotating the hour lines with respect to the origin of
>> the gnomon.
>>
>>
>>
>> Does this make sense?  It sounds like a good project for a 3-D printer.
>>
>>
>>
>> Jack
>>
>>
>>
>> *From:* sundial 
>>  *On Behalf Of *Steve Lelievre
>> *Sent:* Sunday, April 2, 2023 5:16 PM
>> *To:* Michael Ossipoff  
>> *Cc:* Sundial List  
>> *Subject:* Re: Adjusting dial to new location
>>
>>
>>
>> Michael,
>>
>> Yes, I recognize that to get Mean Time involves Equation of Time
>> adjustment and that Equation of Longitude can be handled there to give
>> Standard Time (or DST).
>>
>> But anyway, my inquiry was to seek an online wedge calculator. Nobody
>> identified one and  a week seemed an adequate wait for responses, so I've
>> just written one.  Anyone who's interested, please see
>>
>>
>> https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude
>>
>> Cheers,
>>
>> Steve
>>
>>
>>
>> On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:
>>
>> I just want to mention that the shim under the north or south edge of the
>> dial is only for latitude. Longitude is corrected-for by changing the
>> constant term of the Sundial-Time to Clock-Time conversion.
>>
>>
>>
>> But usually Sundial-Time, Local True Solar Time, is what I’d want from a
>> sundial.
>>
>>
>>
>> On Sun, Mar 26, 2023 at 14:30 Steve Lelievre <
>> steve.lelievre.can...@gmail.com> wrote:
>>
>> Hi,
>>
>> Can anyone point me to an existing online calculator for making a wedge
>> to adjust a horizontal dial to a new latitude and longitude?
>>
>> I am not asking for an explanation of how to do the calculation; I just
>> want to be able to point people to a calculator that has already been
>> proved on the internet. It should use the original location (latitude
>> and longitude) and the new location to calculate the angle of slope of
>> the wedge and the required rotation from the meridian.
>>
>> Many thanks,
>>
>> Steve
>>
>>
>> ---
>> https://lists.uni-koeln.de/mailman/listinfo/sundial
>>
>>
>> ---https://lists.uni-koeln.de/mailman/listinfo/sundial
>>
>> --
> Cell +1 778 837 5771
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
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Re: Adjusting dial to new location

[Michael Ossipoff]

On Tue, Apr 4, 2023 at 08:45  wrote:

> Rotating the dial plate around a vertical axis is wrong because the hours
> lines are not at constant angles.
>
> Rotating the whole dial around the polar axis is the correct way to adjust
> a local solar time dial to a different longitude, the time zone center, for
> example.
>
> Having a dial show the time in a different location is strictly a creative
> choice.
> ---
>
>
> Rotating the dial about the vertical axis & then doing the non-meridian Al
> tipping, in the right combination, is how you get the result that the dial
> is oriented (still in the meridianal-plane) to give Local True Solar Time
> at your standard meridian.
>

I don’t know why anyone would want to do that, unless it’s important to
keep using an old EqT plaque.

> On 2023-04-04 08:44, Jack Aubert via sundial wrote:
>
> Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die
> eigentliche Nachricht steht dadurch in einem Anhang.
>
> This message was wrapped to be DMARC compliant. The actual message
> text is therefore in an attachment.
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[koolish]

Rotating the dial plate around a vertical axis is wrong because the
hours lines are not at constant angles. 


Rotating the whole dial around the polar axis is the correct way to
adjust a local solar time dial to a different longitude, the time zone
center, for example. 


Having a dial show the time in a different location is strictly a
creative choice.

---

On 2023-04-04 08:44, Jack Aubert via sundial wrote:


Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die
eigentliche Nachricht steht dadurch in einem Anhang.

This message was wrapped to be DMARC compliant. The actual message
text is therefore in an attachment. 
---

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https://lists.uni-koeln.de/mailman/listinfo/sundial

RE: Adjusting dial to new location

[Jack Aubert via sundial]

Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die
eigentliche Nachricht steht dadurch in einem Anhang.

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text is therefore in an attachment.--- Begin Message ---
I think I must be missing something here.  I cannot quite wrap my brain around 
what we would be trying to accomplish with a longitude adjustment.

 

A horizontal garden variety dial should tell apparent local solar time as long 
as it is correctly designed and the gnomon is pointing at the north celestial 
pole.  It can be moved to a new location and will continue to tell apparent 
local solar time as long as the whole thing is tilted so that it is at the 
latitude it was designed for and positioned so that the gnomon continues to 
point to the north celestial pole.  Now, If such a dial were to be tilted on 
its other axis so that it corresponds to the original longitude then I think it 
would tell local solar time at the original longitude.  This would appear to be 
wrong since it would not correspond to either local solar time or local civil 
time.   

 

AFAIK, the only way longitude comes into play in the design would be to make 
the dial conform more closely to civil time (leaving aside the equation of 
time) for example if the dial is located near the edge of the time zone.  AFAIK 
the only way to do this is to shift the dial plate around the vertical axis 
originating at the bottom end of the gnomon so that noon is no longer lined up 
with the gnomon and east west are no longer at right angles to the gnomon.  If 
such a dial were relocated then it would need some kind of longitude adjustment 
but would it not then tell something approximating civil time at its old 
location rather than the new one?

 

Is this wrong?  Is it possible to make a local longitude adjustment by tilting 
the whole thing on its polar axis?  

 

My spherical trig is almost nonexistent so I am trying to imagine all this 
visually and cannot quite see how it would work.  It seems to me that an 
east-west wedge would throw the gnomon off its polar axis.  

 

Jack Aubert  

 

 

From: sundial  On Behalf Of Steve Lelievre
Sent: Monday, April 3, 2023 7:47 PM
To: Rod Wall ; kool...@dickkoolish.com
Cc: 'Sundial sundiallist' 
Subject: Re: Adjusting dial to new location

 

Hi, Roderick,

My home internet connection is still non-functional so I can't fix it yet, but 
it does seem that I will have to add an extra test to handle southern 
hemisphere locations and reducing latitudes. Actually, I originally had a 
southern hemisphere check in there but took it out after convincing myself the 
same frame of reference (x axis east, y axis north, z up) applied to the 
spherical trigonometry irrespective of hemisphere. Ho hum.

Steve

 

On 2023-04-03 6:45 a.m., Rod Wall wrote:

Hi Steve,

For both examples below with all sundials at the same Longitude. The 
instructions indicate: 

Place the wedge-sundial assembly on a horizontal surface in a nice sunny 
location. Start with the higher end of the wedge to the north and the sides 
aligned on a north-south line and the sharp edge should be on an east-west line.

Example 1:



If you have a sundial that was designed for Latitude -20 deg. And relocate it 
at Latitude -50 deg.

Would you start with the higher end of the 30 deg wedge to the North. Or would 
it be to the South?



*

Example 2:



If you have a sundial that was designed for Latitude 50 deg. And relocate it at 
20 deg. 



Would you start with the higher end of the 30 deg wedge to the North. Or would 
it be to the South?

*



Please correct me if I am wrong. I think that both examples would be to the 
South.



Roderick.



 

--- End Message ---
---
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Re: Adjusting dial to new location

[Rod Wall]

Hi Steve,

I use to be a member of the NASS but I am retired now. And due to funds 
I was not able to renew my membership. So I don't have access to Fred 
Sawyer's and Bill Gottesman's article.


Maybe the Article and the drawing of the Earth with sundials could be 
used to explain this?


Roderick.

On 3/04/2023 10:26 am, Steve Lelievre wrote:
You don’t need two wedges, you just skew the positioning to do both 
adjustments in one.


If you have The Compendium vol 7 issue 1, take a look at the articles 
by Fred Sawyer and Bill Gottesman.


Steve

On Sun, Apr 2, 2023 at 17:20, Rod Wall  wrote:

Hi Jack and Steve,

To implement what Jack has indicated. You could have two wedges
one on top of each other. One for Latitude correction and one for
Longitude correction.

You could also just use a Longitude correction wedge if you only
wanted to correct for Longitude.

When writing instructions. Please also include people who live in
the southern hemisphere, we do also have sundials.

Do I have this correct?

Roderick.

On 3/04/2023 9:24 am, Steve Lelievre wrote:


Jack,

Try out my calculator! You can specify a time zone meridian for
the dial at its original location, or at its new location, or
both. If there is an effective longitude change, it'll tell you
how to position (twist) the dial on the wedge and how to orient
the wedge itself, turning it away (rotating it ) from the
meridian line.

Steve


On 2023-04-02 3:59 p.m., Jack Aubert wrote:


I thought about this briefly.  I had always thought that the
purpose of the shim or wedge adjustment was to tip the dial
north or south so that dial is at the latitude it was originally
designed for.  If the original dial has a built-in longitude
correction, that could also be factored into a wedge which would
have both a north-south and east-west axis.  But a wedge would
not work if it moved the gnomon out of alignment with the with
the rotation of the earth (or the celestial sphere).  I think a
longitudinal adjustment would only work if he original dial had
a time-zone offset included by rotating the hour lines with
respect to the origin of the gnomon.

Does this make sense?  It sounds like a good project for a 3-D
printer.

Jack

*From:* sundial 
<mailto:sundial-boun...@uni-koeln.de> *On Behalf Of *Steve Lelievre
*Sent:* Sunday, April 2, 2023 5:16 PM
*To:* Michael Ossipoff 
<mailto:email9648...@gmail.com>
*Cc:* Sundial List 
<mailto:sundial@uni-koeln.de>
*Subject:* Re: Adjusting dial to new location

Michael,

Yes, I recognize that to get Mean Time involves Equation of Time
adjustment and that Equation of Longitude can be handled there
to give Standard Time (or DST).

But anyway, my inquiry was to seek an online wedge calculator.
Nobody identified one and  a week seemed an adequate wait for
responses, so I've just written one.  Anyone who's interested,
please see


https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude

Cheers,

Steve

On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:

I just want to mention that the shim under the north or
south edge of the dial is only for latitude. Longitude is
corrected-for by changing the constant term of the
Sundial-Time to Clock-Time conversion.

But usually Sundial-Time, Local True Solar Time, is what I’d
want from a sundial.

On Sun, Mar 26, 2023 at 14:30 Steve Lelievre
 wrote:

Hi,

Can anyone point me to an existing online calculator for
making a wedge
to adjust a horizontal dial to a new latitude and longitude?

I am not asking for an explanation of how to do the
calculation; I just
want to be able to point people to a calculator that has
already been
proved on the internet. It should use the original
location (latitude
and longitude) and the new location to calculate the
angle of slope of
the wedge and the required rotation from the meridian.

Many thanks,

Steve


---
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Re: Adjusting dial to new location

[Rod Wall]

Hi all,

Is the Sundial Mailing list able to accept images?

Below is how we can understand how sundials work. A sundial is a 
mechanical clock. Sundials are geared to the largest clock in the world, 
Earth. Look at it from a mechanical point of view on a spinning Earth.


Draw the earth and cut out paper sundials and place them at different 
Longitudes and see what wedge is needed to keep the style parallel to 
the axis of the Earth.


You can also understand how sundials work in the southern hemisphere. 
The sun still comes up in the East and sets in the West.


Roderick.

On 4/04/2023 12:03 pm, Michael Ossipoff wrote:
That surprises me too. I’d have expected that the only differences 
would be that the dial is numbered counterclockwise, & that north & & 
south are replaced with poleward & equatorward.


On Mon, Apr 3, 2023 at 16:47 Steve Lelievre 
 wrote:


Hi, Roderick,

My home internet connection is still non-functional so I can't fix
it yet, but it does seem that I will have to add an extra test to
handle southern hemisphere locations and reducing latitudes.
Actually, I originally had a southern hemisphere check in there
but took it out after convincing myself the same frame of
reference (x axis east, y axis north, z up) applied to the
spherical trigonometry irrespective of hemisphere. Ho hum.

Steve


On 2023-04-03 6:45 a.m., Rod Wall wrote:


Hi Steve,

For both examples below with all sundials at the same Longitude.
The instructions indicate:

Place the wedge-sundial assembly on a horizontal surface in a
nice sunny location. *Start with the higher end of the wedge to
the north* and the sides aligned on a north-south line and the
sharp edge should be on an east-west line.

Example 1:

If you have a sundial that was designed for Latitude -20 deg. And
relocate it at Latitude -50 deg.

Would you start with the higher end of the 30 deg wedge to the
North. Or would it be to the South?

*

Example 2:

If you have a sundial that was designed for Latitude 50 deg. And
relocate it at 20 deg.

Would you start with the higher end of the 30 deg wedge to the
North. Or would it be to the South?

*

Please correct me if I am wrong. I think that both examples would
be to the South.

Roderick.



---
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---
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Re: Adjusting dial to new location

[Rod Wall]

Hi all,

This link I think is a good way of showing. How we can understand how 
sundials work. A sundial is a mechanical clock. Sundials are geared to 
the largest clock in the world, Earth. Look at it from a mechanical 
point of view on a spinning Earth.


Draw the earth and cut out paper sundials and place them at different 
Longitudes and see what wedge is needed to keep the style parallel to 
the axis of the Earth.


https://www.dropbox.com/s/5loieb818s2dr9o/CCF%20Relocating%20a%20sundial%204%20April%202023.pdf?dl=0

You can also understand how sundials work in the southern hemisphere. 
The sun still comes up in the East and sets in the West.


Roderick

On 4/04/2023 12:03 pm, Michael Ossipoff wrote:
That surprises me too. I’d have expected that the only differences 
would be that the dial is numbered counterclockwise, & that north & & 
south are replaced with poleward & equatorward.


On Mon, Apr 3, 2023 at 16:47 Steve Lelievre 
 wrote:


Hi, Roderick,

My home internet connection is still non-functional so I can't fix
it yet, but it does seem that I will have to add an extra test to
handle southern hemisphere locations and reducing latitudes.
Actually, I originally had a southern hemisphere check in there
but took it out after convincing myself the same frame of
reference (x axis east, y axis north, z up) applied to the
spherical trigonometry irrespective of hemisphere. Ho hum.

Steve


On 2023-04-03 6:45 a.m., Rod Wall wrote:


Hi Steve,

For both examples below with all sundials at the same Longitude.
The instructions indicate:

Place the wedge-sundial assembly on a horizontal surface in a
nice sunny location. *Start with the higher end of the wedge to
the north* and the sides aligned on a north-south line and the
sharp edge should be on an east-west line.

Example 1:

If you have a sundial that was designed for Latitude -20 deg. And
relocate it at Latitude -50 deg.

Would you start with the higher end of the 30 deg wedge to the
North. Or would it be to the South?

*

Example 2:

If you have a sundial that was designed for Latitude 50 deg. And
relocate it at 20 deg.

Would you start with the higher end of the 30 deg wedge to the
North. Or would it be to the South?

*

Please correct me if I am wrong. I think that both examples would
be to the South.

Roderick.



---
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---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[Michael Ossipoff]

That surprises me too. I’d have expected that the only differences would be
that the dial is numbered counterclockwise, & that north & & south are
replaced with poleward & equatorward.

On Mon, Apr 3, 2023 at 16:47 Steve Lelievre 
wrote:

> Hi, Roderick,
>
> My home internet connection is still non-functional so I can't fix it yet,
> but it does seem that I will have to add an extra test to handle southern
> hemisphere locations and reducing latitudes. Actually, I originally had a
> southern hemisphere check in there but took it out after convincing myself
> the same frame of reference (x axis east, y axis north, z up) applied to
> the spherical trigonometry irrespective of hemisphere. Ho hum.
>
> Steve
>
>
> On 2023-04-03 6:45 a.m., Rod Wall wrote:
>
> Hi Steve,
>
> For both examples below with all sundials at the same Longitude. The
> instructions indicate:
>
> Place the wedge-sundial assembly on a horizontal surface in a nice sunny
> location. *Start with the higher end of the wedge to the north* and the
> sides aligned on a north-south line and the sharp edge should be on an
> east-west line.
>
> Example 1:
>
> If you have a sundial that was designed for Latitude -20 deg. And relocate
> it at Latitude -50 deg.
>
> Would you start with the higher end of the 30 deg wedge to the North. Or
> would it be to the South?
>
> *
>
> Example 2:
>
> If you have a sundial that was designed for Latitude 50 deg. And relocate
> it at 20 deg.
>
> Would you start with the higher end of the 30 deg wedge to the North. Or
> would it be to the South?
>
> *
>
> Please correct me if I am wrong. I think that both examples would be to
> the South.
>
> Roderick.
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
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Re: Adjusting dial to new location

[Steve Lelievre]

Hi, Roderick,

My home internet connection is still non-functional so I can't fix it 
yet, but it does seem that I will have to add an extra test to handle 
southern hemisphere locations and reducing latitudes. Actually, I 
originally had a southern hemisphere check in there but took it out 
after convincing myself the same frame of reference (x axis east, y axis 
north, z up) applied to the spherical trigonometry irrespective of 
hemisphere. Ho hum.


Steve


On 2023-04-03 6:45 a.m., Rod Wall wrote:


Hi Steve,

For both examples below with all sundials at the same Longitude. The 
instructions indicate:


Place the wedge-sundial assembly on a horizontal surface in a nice 
sunny location. *Start with the higher end of the wedge to the north* 
and the sides aligned on a north-south line and the sharp edge should 
be on an east-west line.


Example 1:

If you have a sundial that was designed for Latitude -20 deg. And 
relocate it at Latitude -50 deg.


Would you start with the higher end of the 30 deg wedge to the North. 
Or would it be to the South?


*

Example 2:

If you have a sundial that was designed for Latitude 50 deg. And 
relocate it at 20 deg.


Would you start with the higher end of the 30 deg wedge to the North. 
Or would it be to the South?


*

Please correct me if I am wrong. I think that both examples would be 
to the South.


Roderick.

---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[koolish]

Steve tells me that the lack of longitude correction instructions was
due to my choice of 'local solar time' as the time indication. When I
use 'UTC-5' I get the instructions.

---

On 2023-04-02 21:30, kool...@dickkoolish.com wrote:

I tried the app. I used 40, -75 and 45, -70. It just said to use a 5 degree wedge and said nothing about a longitude correction. 

I communicated to Steve privately last week. I said that a longitude correction was a rotation around the gnomon. Does anybody else believe this? One of the books, I can't remember which, calls this The Universal Sundial Principle. It says that two dials with the same orientation in space with respect to the sun will read the same time, regardless of where on earth they are. 


---

On 2023-04-02 19:24, Steve Lelievre wrote: 

Jack, 

Try out my calculator! You can specify a time zone meridian for the dial at its original location, or at its new location, or both. If there is an effective longitude change, it'll tell you how to position (twist) the dial on the wedge and how to orient the wedge itself, turning it away (rotating it ) from the meridian line. 

Steve 

On 2023-04-02 3:59 p.m., Jack Aubert wrote: 

I thought about this briefly.  I had always thought that the purpose of the shim or wedge adjustment was to tip the dial north or south so that dial is at the latitude it was originally designed for.  If the original dial has a built-in longitude correction, that could also be factored into a wedge which would have both a north-south and east-west axis.  But a wedge would not work if it moved the gnomon out of alignment with the with the rotation of the earth (or the celestial sphere).  I think a longitudinal adjustment would only work if he original dial had a time-zone offset included by rotating the hour lines with respect to the origin of the gnomon.  

Does this make sense?  It sounds like a good project for a 3-D printer.

Jack 


From: sundial  On Behalf Of Steve Lelievre
Sent: Sunday, April 2, 2023 5:16 PM
To: Michael Ossipoff 
Cc: Sundial List 
Subject: Re: Adjusting dial to new location 

Michael, 

Yes, I recognize that to get Mean Time involves Equation of Time adjustment and that Equation of Longitude can be handled there to give Standard Time (or DST). 

But anyway, my inquiry was to seek an online wedge calculator. Nobody identified one and  a week seemed an adequate wait for responses, so I've just written one.  Anyone who's interested, please see 

https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude 

Cheers, 

Steve 

On 2023-04-02 1:41 p.m., Michael Ossipoff wrote: 

I just want to mention that the shim under the north or south edge of the dial is only for latitude. Longitude is corrected-for by changing the constant term of the Sundial-Time to Clock-Time conversion. 

But usually Sundial-Time, Local True Solar Time, is what I'd want from a sundial. 

On Sun, Mar 26, 2023 at 14:30 Steve Lelievre  wrote: 


Hi,

Can anyone point me to an existing online calculator for making a wedge 
to adjust a horizontal dial to a new latitude and longitude?


I am not asking for an explanation of how to do the calculation; I just 
want to be able to point people to a calculator that has already been 
proved on the internet. It should use the original location (latitude 
and longitude) and the new location to calculate the angle of slope of 
the wedge and the required rotation from the meridian.


Many thanks,

Steve

---
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---
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---
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Re: Adjusting dial to new location

[Rod Wall]

Hi Steve,

For both examples below with all sundials at the same Longitude. The 
instructions indicate:


Place the wedge-sundial assembly on a horizontal surface in a nice sunny 
location. *Start with the higher end of the wedge to the north* and the 
sides aligned on a north-south line and the sharp edge should be on an 
east-west line.


Example 1:

If you have a sundial that was designed for Latitude -20 deg. And 
relocate it at Latitude -50 deg.


Would you start with the higher end of the 30 deg wedge to the North. Or 
would it be to the South?


*

Example 2:

If you have a sundial that was designed for Latitude 50 deg. And 
relocate it at 20 deg.


Would you start with the higher end of the 30 deg wedge to the North. Or 
would it be to the South?


*

Please correct me if I am wrong. I think that both examples would be to 
the South.


Roderick.

---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[Michael Ossipoff]

Tipping the dial-plate for latitude makes it exactly as if the dial were at
the latitude it was made for. No need for a 2nd wedge. If the new longitude
differs from the old on, then just adjust your longitude correction
constant. + 4 minutes for every degree more west of your standard meridian.

On Sun, Apr 2, 2023 at 17:20 Rod Wall  wrote:

> Hi Jack and Steve,
>
> To implement what Jack has indicated. You could have two wedges one on top
> of each other. One for Latitude correction and one for Longitude correction.
>
> You could also just use a Longitude correction wedge if you only wanted to
> correct for Longitude.
>
> When writing instructions. Please also include people who live in the
> southern hemisphere, we do also have sundials.
>
> Do I have this correct?
>
> Roderick.
>
> On 3/04/2023 9:24 am, Steve Lelievre wrote:
>
> Jack,
>
> Try out my calculator! You can specify a time zone meridian for the dial
> at its original location, or at its new location, or both. If there is an
> effective longitude change, it'll tell you how to position (twist) the dial
> on the wedge and how to orient the wedge itself, turning it away (rotating
> it ) from the meridian line.
>
> Steve
>
>
> On 2023-04-02 3:59 p.m., Jack Aubert wrote:
>
> I thought about this briefly.  I had always thought that the purpose of
> the shim or wedge adjustment was to tip the dial north or south so that
> dial is at the latitude it was originally designed for.  If the original
> dial has a built-in longitude correction, that could also be factored into
> a wedge which would have both a north-south and east-west axis.  But a
> wedge would not work if it moved the gnomon out of alignment with the with
> the rotation of the earth (or the celestial sphere).  I think a
> longitudinal adjustment would only work if he original dial had a time-zone
> offset included by rotating the hour lines with respect to the origin of
> the gnomon.
>
>
>
> Does this make sense?  It sounds like a good project for a 3-D printer.
>
>
>
> Jack
>
>
>
> *From:* sundial 
>  *On Behalf Of *Steve Lelievre
> *Sent:* Sunday, April 2, 2023 5:16 PM
> *To:* Michael Ossipoff  
> *Cc:* Sundial List  
> *Subject:* Re: Adjusting dial to new location
>
>
>
> Michael,
>
> Yes, I recognize that to get Mean Time involves Equation of Time
> adjustment and that Equation of Longitude can be handled there to give
> Standard Time (or DST).
>
> But anyway, my inquiry was to seek an online wedge calculator. Nobody
> identified one and  a week seemed an adequate wait for responses, so I've
> just written one.  Anyone who's interested, please see
>
>
> https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude
>
> Cheers,
>
> Steve
>
>
>
> On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:
>
> I just want to mention that the shim under the north or south edge of the
> dial is only for latitude. Longitude is corrected-for by changing the
> constant term of the Sundial-Time to Clock-Time conversion.
>
>
>
> But usually Sundial-Time, Local True Solar Time, is what I’d want from a
> sundial.
>
>
>
> On Sun, Mar 26, 2023 at 14:30 Steve Lelievre <
> steve.lelievre.can...@gmail.com> wrote:
>
> Hi,
>
> Can anyone point me to an existing online calculator for making a wedge
> to adjust a horizontal dial to a new latitude and longitude?
>
> I am not asking for an explanation of how to do the calculation; I just
> want to be able to point people to a calculator that has already been
> proved on the internet. It should use the original location (latitude
> and longitude) and the new location to calculate the angle of slope of
> the wedge and the required rotation from the meridian.
>
> Many thanks,
>
> Steve
>
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
> ---https://lists.uni-koeln.de/mailman/listinfo/sundial
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[koolish]

I tried the app. I used 40, -75 and 45, -70. It just said to use a 5
degree wedge and said nothing about a longitude correction. 


I communicated to Steve privately last week. I said that a longitude
correction was a rotation around the gnomon. Does anybody else believe
this? One of the books, I can't remember which, calls this The Universal
Sundial Principle. It says that two dials with the same orientation in
space with respect to the sun will read the same time, regardless of
where on earth they are. 


---

On 2023-04-02 19:24, Steve Lelievre wrote:

Jack, 

Try out my calculator! You can specify a time zone meridian for the dial at its original location, or at its new location, or both. If there is an effective longitude change, it'll tell you how to position (twist) the dial on the wedge and how to orient the wedge itself, turning it away (rotating it ) from the meridian line. 

Steve 

On 2023-04-02 3:59 p.m., Jack Aubert wrote: 

I thought about this briefly.  I had always thought that the purpose of the shim or wedge adjustment was to tip the dial north or south so that dial is at the latitude it was originally designed for.  If the original dial has a built-in longitude correction, that could also be factored into a wedge which would have both a north-south and east-west axis.  But a wedge would not work if it moved the gnomon out of alignment with the with the rotation of the earth (or the celestial sphere).  I think a longitudinal adjustment would only work if he original dial had a time-zone offset included by rotating the hour lines with respect to the origin of the gnomon.  

Does this make sense?  It sounds like a good project for a 3-D printer.

Jack 


From: sundial  On Behalf Of Steve Lelievre
Sent: Sunday, April 2, 2023 5:16 PM
To: Michael Ossipoff 
Cc: Sundial List 
Subject: Re: Adjusting dial to new location 

Michael, 

Yes, I recognize that to get Mean Time involves Equation of Time adjustment and that Equation of Longitude can be handled there to give Standard Time (or DST). 

But anyway, my inquiry was to seek an online wedge calculator. Nobody identified one and  a week seemed an adequate wait for responses, so I've just written one.  Anyone who's interested, please see 

https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude 

Cheers, 

Steve 

On 2023-04-02 1:41 p.m., Michael Ossipoff wrote: 

I just want to mention that the shim under the north or south edge of the dial is only for latitude. Longitude is corrected-for by changing the constant term of the Sundial-Time to Clock-Time conversion. 

But usually Sundial-Time, Local True Solar Time, is what I'd want from a sundial. 

On Sun, Mar 26, 2023 at 14:30 Steve Lelievre  wrote: 


Hi,

Can anyone point me to an existing online calculator for making a wedge 
to adjust a horizontal dial to a new latitude and longitude?


I am not asking for an explanation of how to do the calculation; I just 
want to be able to point people to a calculator that has already been 
proved on the internet. It should use the original location (latitude 
and longitude) and the new location to calculate the angle of slope of 
the wedge and the required rotation from the meridian.


Many thanks,

Steve

---
https://lists.uni-koeln.de/mailman/listinfo/sundial


---
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Re: Sundial in walking stick

[Peter Mayer]

Hi Patrick,

Thanks for the link. It certainly seems similar, if slightly different, 
from what I take to be the Indian 'knockoff' that you've found. Perhaps 
we should all get one...for future use!


It does seem evident that these are all made for the higher latitudes in 
the Northern Hemisphere. So I tried to imagine using it horizontally as 
a vertical dial for Down Under.


I'll let you know what it went for after the auction tomorrow.

best wishes,

Peter

On 3/04/2023 2:00:33, Patrick Vyvyan wrote:

*
CAUTION: External email. Only click on links or open attachments from 
trusted senders.

*

Rather curious to know what it makes finally, from what I can see it 
looks to be a modern novelty very similar to this one currently out of 
stock on the Internet 
https://www.alibaba.com/product-detail/Vintage-Brass-and-Wood-Sundial-Compass_1006081836.html 



Best wishes to all, Patrick Vyvyan

On Sun, 2 Apr 2023 at 06:41, Peter Mayer  wrote:

Hi,

This walking stick with sundial, compass (and flask) is coming up
for sale at an Adelaide auction house. Bids are already above
their modest estimate of sale price.


best wishes,

Peter

-- 
---

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School of Social Sciences
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The University of Adelaide, AUSTRALIA 5005
Ph : +61 8 8313 5609
Fax : +61 8 8313 3443
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--
---
Peter Mayer
Department of Politics & International Relations (POLIR)
School of Social Sciences
http://www.arts.adelaide.edu.au/polis/
The University of Adelaide, AUSTRALIA 5005
Ph : +61 8 8313 5609
Fax : +61 8 8313 3443
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Re: Adjusting dial to new location

[Steve Lelievre]

You don’t need two wedges, you just skew the positioning to do both
adjustments in one.

If you have The Compendium vol 7 issue 1, take a look at the articles by
Fred Sawyer and Bill Gottesman.

Steve

On Sun, Apr 2, 2023 at 17:20, Rod Wall  wrote:

> Hi Jack and Steve,
>
> To implement what Jack has indicated. You could have two wedges one on top
> of each other. One for Latitude correction and one for Longitude correction.
>
> You could also just use a Longitude correction wedge if you only wanted to
> correct for Longitude.
>
> When writing instructions. Please also include people who live in the
> southern hemisphere, we do also have sundials.
>
> Do I have this correct?
>
> Roderick.
>
> On 3/04/2023 9:24 am, Steve Lelievre wrote:
>
> Jack,
>
> Try out my calculator! You can specify a time zone meridian for the dial
> at its original location, or at its new location, or both. If there is an
> effective longitude change, it'll tell you how to position (twist) the dial
> on the wedge and how to orient the wedge itself, turning it away (rotating
> it ) from the meridian line.
>
> Steve
>
>
> On 2023-04-02 3:59 p.m., Jack Aubert wrote:
>
> I thought about this briefly.  I had always thought that the purpose of
> the shim or wedge adjustment was to tip the dial north or south so that
> dial is at the latitude it was originally designed for.  If the original
> dial has a built-in longitude correction, that could also be factored into
> a wedge which would have both a north-south and east-west axis.  But a
> wedge would not work if it moved the gnomon out of alignment with the with
> the rotation of the earth (or the celestial sphere).  I think a
> longitudinal adjustment would only work if he original dial had a time-zone
> offset included by rotating the hour lines with respect to the origin of
> the gnomon.
>
>
>
> Does this make sense?  It sounds like a good project for a 3-D printer.
>
>
>
> Jack
>
>
>
> *From:* sundial 
>  *On Behalf Of *Steve Lelievre
> *Sent:* Sunday, April 2, 2023 5:16 PM
> *To:* Michael Ossipoff  
> *Cc:* Sundial List  
> *Subject:* Re: Adjusting dial to new location
>
>
>
> Michael,
>
> Yes, I recognize that to get Mean Time involves Equation of Time
> adjustment and that Equation of Longitude can be handled there to give
> Standard Time (or DST).
>
> But anyway, my inquiry was to seek an online wedge calculator. Nobody
> identified one and  a week seemed an adequate wait for responses, so I've
> just written one.  Anyone who's interested, please see
>
>
> https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude
>
> Cheers,
>
> Steve
>
>
>
> On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:
>
> I just want to mention that the shim under the north or south edge of the
> dial is only for latitude. Longitude is corrected-for by changing the
> constant term of the Sundial-Time to Clock-Time conversion.
>
>
>
> But usually Sundial-Time, Local True Solar Time, is what I’d want from a
> sundial.
>
>
>
> On Sun, Mar 26, 2023 at 14:30 Steve Lelievre <
> steve.lelievre.can...@gmail.com> wrote:
>
> Hi,
>
> Can anyone point me to an existing online calculator for making a wedge
> to adjust a horizontal dial to a new latitude and longitude?
>
> I am not asking for an explanation of how to do the calculation; I just
> want to be able to point people to a calculator that has already been
> proved on the internet. It should use the original location (latitude
> and longitude) and the new location to calculate the angle of slope of
> the wedge and the required rotation from the meridian.
>
> Many thanks,
>
> Steve
>
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
> ---https://lists.uni-koeln.de/mailman/listinfo/sundial
>
> --
Cell +1 778 837 5771
---
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Re: Adjusting dial to new location

[Rod Wall]

Hi Jack and Steve,

To implement what Jack has indicated. You could have two wedges one on 
top of each other. One for Latitude correction and one for Longitude 
correction.


You could also just use a Longitude correction wedge if you only wanted 
to correct for Longitude.


When writing instructions. Please also include people who live in the 
southern hemisphere, we do also have sundials.


Do I have this correct?

Roderick.

On 3/04/2023 9:24 am, Steve Lelievre wrote:


Jack,

Try out my calculator! You can specify a time zone meridian for the 
dial at its original location, or at its new location, or both. If 
there is an effective longitude change, it'll tell you how to position 
(twist) the dial on the wedge and how to orient the wedge itself, 
turning it away (rotating it ) from the meridian line.


Steve


On 2023-04-02 3:59 p.m., Jack Aubert wrote:


I thought about this briefly.  I had always thought that the purpose 
of the shim or wedge adjustment was to tip the dial north or south so 
that dial is at the latitude it was originally designed for.  If the 
original dial has a built-in longitude correction, that could also be 
factored into a wedge which would have both a north-south and 
east-west axis.  But a wedge would not work if it moved the gnomon 
out of alignment with the with the rotation of the earth (or the 
celestial sphere).  I think a longitudinal adjustment would only work 
if he original dial had a time-zone offset included by rotating the 
hour lines with respect to the origin of the gnomon.


Does this make sense?  It sounds like a good project for a 3-D printer.

Jack

*From:* sundial  *On Behalf Of *Steve 
Lelievre

*Sent:* Sunday, April 2, 2023 5:16 PM
*To:* Michael Ossipoff 
*Cc:* Sundial List 
*Subject:* Re: Adjusting dial to new location

Michael,

Yes, I recognize that to get Mean Time involves Equation of Time 
adjustment and that Equation of Longitude can be handled there to 
give Standard Time (or DST).


But anyway, my inquiry was to seek an online wedge calculator. Nobody 
identified one and  a week seemed an adequate wait for responses, so 
I've just written one. Anyone who's interested, please see


https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude

Cheers,

Steve

On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:

I just want to mention that the shim under the north or south
edge of the dial is only for latitude. Longitude is corrected-for
by changing the constant term of the Sundial-Time to Clock-Time
conversion.

But usually Sundial-Time, Local True Solar Time, is what I’d want
from a sundial.

On Sun, Mar 26, 2023 at 14:30 Steve Lelievre
 wrote:

Hi,

Can anyone point me to an existing online calculator for
making a wedge
to adjust a horizontal dial to a new latitude and longitude?

I am not asking for an explanation of how to do the
calculation; I just
want to be able to point people to a calculator that has
already been
proved on the internet. It should use the original location
(latitude
and longitude) and the new location to calculate the angle of
slope of
the wedge and the required rotation from the meridian.

Many thanks,

Steve


---
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Re: RE: Adjusting dial to new location

[Steve Lelievre]

Jack,

Try out my calculator! You can specify a time zone meridian for the dial 
at its original location, or at its new location, or both. If there is 
an effective longitude change, it'll tell you how to position (twist) 
the dial on the wedge and how to orient the wedge itself, turning it 
away (rotating it ) from the meridian line.


Steve


On 2023-04-02 3:59 p.m., Jack Aubert wrote:


I thought about this briefly.  I had always thought that the purpose 
of the shim or wedge adjustment was to tip the dial north or south so 
that dial is at the latitude it was originally designed for.  If the 
original dial has a built-in longitude correction, that could also be 
factored into a wedge which would have both a north-south and 
east-west axis.  But a wedge would not work if it moved the gnomon out 
of alignment with the with the rotation of the earth (or the celestial 
sphere).  I think a longitudinal adjustment would only work if he 
original dial had a time-zone offset included by rotating the hour 
lines with respect to the origin of the gnomon.


Does this make sense?  It sounds like a good project for a 3-D printer.

Jack

*From:* sundial  *On Behalf Of *Steve 
Lelievre

*Sent:* Sunday, April 2, 2023 5:16 PM
*To:* Michael Ossipoff 
*Cc:* Sundial List 
*Subject:* Re: Adjusting dial to new location

Michael,

Yes, I recognize that to get Mean Time involves Equation of Time 
adjustment and that Equation of Longitude can be handled there to give 
Standard Time (or DST).


But anyway, my inquiry was to seek an online wedge calculator. Nobody 
identified one and  a week seemed an adequate wait for responses, so 
I've just written one.  Anyone who's interested, please see


https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude

Cheers,

Steve

On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:

I just want to mention that the shim under the north or south edge
of the dial is only for latitude. Longitude is corrected-for by
changing the constant term of the Sundial-Time to Clock-Time
conversion.

But usually Sundial-Time, Local True Solar Time, is what I’d want
from a sundial.

On Sun, Mar 26, 2023 at 14:30 Steve Lelievre
 wrote:

Hi,

Can anyone point me to an existing online calculator for
making a wedge
to adjust a horizontal dial to a new latitude and longitude?

I am not asking for an explanation of how to do the
calculation; I just
want to be able to point people to a calculator that has
already been
proved on the internet. It should use the original location
(latitude
and longitude) and the new location to calculate the angle of
slope of
the wedge and the required rotation from the meridian.

Many thanks,

Steve


---
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---
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RE: Adjusting dial to new location

[Jack Aubert via sundial]

Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die
eigentliche Nachricht steht dadurch in einem Anhang.

This message was wrapped to be DMARC compliant. The actual message
text is therefore in an attachment.--- Begin Message ---
I thought about this briefly.  I had always thought that the purpose of the 
shim or wedge adjustment was to tip the dial north or south so that dial is at 
the latitude it was originally designed for.  If the original dial has a 
built-in longitude correction, that could also be factored into a wedge which 
would have both a north-south and east-west axis.  But a wedge would not work 
if it moved the gnomon out of alignment with the with the rotation of the earth 
(or the celestial sphere).  I think a longitudinal adjustment would only work 
if he original dial had a time-zone offset included by rotating the hour lines 
with respect to the origin of the gnomon.  

 

Does this make sense?  It sounds like a good project for a 3-D printer.   

 

Jack

 

From: sundial  On Behalf Of Steve Lelievre
Sent: Sunday, April 2, 2023 5:16 PM
To: Michael Ossipoff 
Cc: Sundial List 
Subject: Re: Adjusting dial to new location

 

Michael,

Yes, I recognize that to get Mean Time involves Equation of Time adjustment and 
that Equation of Longitude can be handled there to give Standard Time (or DST).

But anyway, my inquiry was to seek an online wedge calculator. Nobody 
identified one and  a week seemed an adequate wait for responses, so I've just 
written one.  Anyone who's interested, please see

https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude

Cheers,

Steve

 

On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:

I just want to mention that the shim under the north or south edge of the dial 
is only for latitude. Longitude is corrected-for by changing the constant term 
of the Sundial-Time to Clock-Time conversion.

 

But usually Sundial-Time, Local True Solar Time, is what I’d want from a 
sundial.

 

On Sun, Mar 26, 2023 at 14:30 Steve Lelievre mailto:steve.lelievre.can...@gmail.com> > wrote:

Hi,

Can anyone point me to an existing online calculator for making a wedge 
to adjust a horizontal dial to a new latitude and longitude?

I am not asking for an explanation of how to do the calculation; I just 
want to be able to point people to a calculator that has already been 
proved on the internet. It should use the original location (latitude 
and longitude) and the new location to calculate the angle of slope of 
the wedge and the required rotation from the meridian.

Many thanks,

Steve


---
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--- End Message ---
---
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Re: Adjusting dial to new location

[Michael Ossipoff]

...& thank you for doing so, because online calculators & dial-printing
programs make sundials readily accessible to everyone.

On Sun, Apr 2, 2023 at 5:15 PM Steve Lelievre <
steve.lelievre.can...@gmail.com> wrote:

> Michael,
>
> Yes, I recognize that to get Mean Time involves Equation of Time
> adjustment and that Equation of Longitude can be handled there to give
> Standard Time (or DST).
>
> But anyway, my inquiry was to seek an online wedge calculator. Nobody
> identified one and  a week seemed an adequate wait for responses, so I've
> just written one.  Anyone who's interested, please see
>
>
> https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude
>
> Cheers,
>
> Steve
>
> On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:
>
> I just want to mention that the shim under the north or south edge of the
> dial is only for latitude. Longitude is corrected-for by changing the
> constant term of the Sundial-Time to Clock-Time conversion.
>
> But usually Sundial-Time, Local True Solar Time, is what I’d want from a
> sundial.
>
> On Sun, Mar 26, 2023 at 14:30 Steve Lelievre <
> steve.lelievre.can...@gmail.com> wrote:
>
>> Hi,
>>
>> Can anyone point me to an existing online calculator for making a wedge
>> to adjust a horizontal dial to a new latitude and longitude?
>>
>> I am not asking for an explanation of how to do the calculation; I just
>> want to be able to point people to a calculator that has already been
>> proved on the internet. It should use the original location (latitude
>> and longitude) and the new location to calculate the angle of slope of
>> the wedge and the required rotation from the meridian.
>>
>> Many thanks,
>>
>> Steve
>>
>>
>> ---
>> https://lists.uni-koeln.de/mailman/listinfo/sundial
>>
>>
---
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Re: Adjusting dial to new location

[Steve Lelievre]

Michael,

Yes, I recognize that to get Mean Time involves Equation of Time 
adjustment and that Equation of Longitude can be handled there to give 
Standard Time (or DST).


But anyway, my inquiry was to seek an online wedge calculator. Nobody 
identified one and  a week seemed an adequate wait for responses, so 
I've just written one.  Anyone who's interested, please see


https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude

Cheers,

Steve


On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:
I just want to mention that the shim under the north or south edge of 
the dial is only for latitude. Longitude is corrected-for by changing 
the constant term of the Sundial-Time to Clock-Time conversion.


But usually Sundial-Time, Local True Solar Time, is what I’d want from 
a sundial.


On Sun, Mar 26, 2023 at 14:30 Steve Lelievre 
 wrote:


Hi,

Can anyone point me to an existing online calculator for making a
wedge
to adjust a horizontal dial to a new latitude and longitude?

I am not asking for an explanation of how to do the calculation; I
just
want to be able to point people to a calculator that has already been
proved on the internet. It should use the original location (latitude
and longitude) and the new location to calculate the angle of
slope of
the wedge and the required rotation from the meridian.

Many thanks,

Steve


---
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---
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Re: Adjusting dial to new location

[Michael Ossipoff]

I just want to mention that the shim under the north or south edge of the
dial is only for latitude. Longitude is corrected-for by changing the
constant term of the Sundial-Time to Clock-Time conversion.

But usually Sundial-Time, Local True Solar Time, is what I’d want from a
sundial.

On Sun, Mar 26, 2023 at 14:30 Steve Lelievre <
steve.lelievre.can...@gmail.com> wrote:

> Hi,
>
> Can anyone point me to an existing online calculator for making a wedge
> to adjust a horizontal dial to a new latitude and longitude?
>
> I am not asking for an explanation of how to do the calculation; I just
> want to be able to point people to a calculator that has already been
> proved on the internet. It should use the original location (latitude
> and longitude) and the new location to calculate the angle of slope of
> the wedge and the required rotation from the meridian.
>
> Many thanks,
>
> Steve
>
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Sundial in walking stick

[Patrick Vyvyan]

Rather curious to know what it makes finally, from what I can see it looks
to be a modern novelty very similar to this one currently out of stock on
the Internet
https://www.alibaba.com/product-detail/Vintage-Brass-and-Wood-Sundial-Compass_1006081836.html

Best wishes to all, Patrick Vyvyan

On Sun, 2 Apr 2023 at 06:41, Peter Mayer  wrote:

> Hi,
>
> This walking stick with sundial, compass (and flask) is coming up for sale
> at an Adelaide auction house. Bids are already above their modest estimate
> of sale price.
>
>
> best wishes,
>
> Peter
>
> --
> ---
> Peter Mayer
> Department of Politics & International Relations (POLIR)
> School of Social Scienceshttp://www.arts.adelaide.edu.au/polis/
> The University of Adelaide, AUSTRALIA 5005
> Ph : +61 8 8313 5609
> Fax : +61 8 8313 3443
> e-mail: peter.ma...@adelaide.edu.au
> CRICOS Provider Number 00123M
> ---
>
> This email message is intended only for the addressee(s)
> and contains information that may be confidential
> and/or copyright. If you are not the intended recipient
> please notify the sender by reply email
> and immediately delete this email.
> Use, disclosure or reproduction of this email by anyone
> other than the intended recipient(s) is strictly prohibited.
> No representation is made that this email or any attachment
> are free of viruses. Virus scanning is recommended and is the
> responsibility of the recipient.
> --https://www.adelaide.edu.au/study/
>
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>
>
---
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Re: Ice Sundial

[tkreyche]

Beautiful! With some additional markers, it could become an azimuthal dial. I'm not planning a trek to the site - maybe a digital overlay.On Mar 9, 2023 9:58 AM, Werner Riegler  wrote:
Dear Dialists,


On this link 
https://news.artnet.com/style/artist-daniel-arsham-hublots-new-brand-ambassador-just-installed-a-massive-crystal-sundial-high-in-the-swiss-alps-2267460
your see a ’sundial’ made in Switzerland. It’s looks beautful, but it is not really a dial. I would call it a ’timeless’ piece of art …


best regards
Werner




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Re: Spring issue of "Cadrans solaires pour tous"

[ro...@torrenti.net]

My below message hasn’t been distributed, is there any reason ?
Best regards

De : ro...@torrenti.net 
Date : jeudi, 2 mars 2023 à 09:28
À : Sundial List 
Objet : Spring issue of "Cadrans solaires pour tous"
Dear colleagues,

I am very glad to send you the digital version (pdf file) of the latest issue 
(n°7) of the « Cadrans solaires pour tous” magazine. This file can also be 
freely downloaded from https://www.cadrans-solaires.info/le-magazine/.

This issue namely includes the announcement of our “2023 photo contest”. Please 
consider participating!

Warm regards

Roger Torrenti

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Re: No more leap seconds!

[Michael Ossipoff]

I'd rather keep the leap-second. The fluctuation that it brings to
clock-time only has a 1-second peak-to-peak amplitude. That's completely
insignificant to dialists.   & also entirely insignificant for such
things as Sunrise, Sunset, Civil-Twilight & Nautical Twilight, where a
cloud or a little mist can change the illumination a lot more than a few
seconds of time.

If they switch to leap-minutes, then we'll have to deal with a 3rd
non-negligible component to the difference between clock-time & True-Solar
Time.  Now it's the longitude-correction & the EqT.  But when they switch
from leap-seconds to leap-minute, there'll be a 3rd non-negligible
component: The component resulting from the long-accumulated drift or the
abrupt 1-minute correction.

Though of course the leap-second deals with variations in the
day-length,I've heard (but not verified) that actually most of what the
leap-seconds are doing is correcting for the fact that our average
day-length differs from what it was in the early 19th century, when it was
the basis of  the official precise-timekeeping second.

Since that day, our diurnal-astronomical second (1/86,400 of a mean-solar
day) has changed enough that the leap-second is needed to compensate for
the amount by which the diurnal-astronomical second has changed since the
timekeeping-second standard was set in the early 19th century.

The scientists might have very good reasons why leap-minutes would work
better for them. But not for dialists or people interested in the time of
Sunrise, Sunset, Civil-Twilight & Nautical-Twilight.

On Thu, Nov 24, 2022 at 4:54 AM fabio.sav...@nonvedolora.it <
fabio.sav...@nonvedolora.it> wrote:

> Dear all, I have never commented on this topic, I do it now with a
> proposal.
>
> - The leap second takes into account a sort of 'noise', unpredictable
> before, for small variations in the speed of the Earth's rotation.
> Anyway, over the millennia this speed will decrease, so the leap second is
> not enough but the 'physical' second will deviate from the 'astronomical'
> one.
> The physical one is necessary to measure the astronomical one and they are
> two different things despite the attempts of recent centuries to make them
> equivalent
>
> - Martian days have a different second, residents will use the physical
> second as unit of measurement for their scientific instrument but they will
> want to live a 24-hour day (in any case full hours) with an astronomical
> second significantly different from the physical one.
>
> - At the end of the 18th century the meter was calibrated as 1/1 of
> the distance between the equator and the pole, it was later found that the
> measurement is a few kilometers more and also changes from one meridian to
> another, not to mention the equator.
> This did not change the unit of measurement and did not impose a wrong
> measurement of the Earth. It is accepted that the meter has an autonomous
> definition distinct from the geographic measurements of the planet.
>
> In my opinion the problem is in the name: the 'second' is a name that
> derives from a fraction of the day while the physical second is a unit of
> measurement that is still unnamed.
> If the physical second had a definition, it would help put an end once and
> for all between the demands of scientific measurement and the rhythm of a
> planet's days.
> The gnomonists are the most focused community on the history of time for
> which I am launching a proposal:
> help the scientific world to find a definition for the physical second,
> giving it a separate identity from the local astronomical second (Earth,
> Mars, etc.).
> This forum could be the place to put forward some shared proposal and
> start using it.
> It does not matter if the scientific community wants to change it, it
> would still be a success to have established that the physical second has a
> different name and identity from our dear old terrestrial second. That of
> clocks and sundials, and of our terrestrial life.
>
> Long live the second, ciao Fabio
>
>
> Il 21/11/2022 17:39, Steve Lelievre ha scritto:
>
>
> Ah, the joys of Listservs and email software. My participation sometimes
> gets of of step too: occasionally, original posts reach me after other
> people's replies.
>
> Perhaps it wouldn't be a problem if all the world's computers were exactly
> synchronized... perhaps they could use atomic clocks for that   ;-)
>
> Cheers,
>
> Steve
>
>
> On 2022-11-21 12:04 a.m., John Pickard wrote:
>
> Sorry Steve,
>
> I sent my post before seeing yours.
>
> --
> Cheers, John.
>
> Dr John Pickard.
>
>
>
> ---https://lists.uni-koeln.de/mailman/listinfo/sundial
>
> --
> Fabio savianfabio.sav...@nonvedolora.itwww.nonvedolora.eu
> Paderno Dugnano, Milano, Italy
> 45° 34' 9'' N, 9° 9' 54'' E, UTC +1 (DST +2)
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>

Re: What is purpose of the shaded area on the face of this sundial in Agra?

[Steve Lelievre]

Bill,

On 2022-12-09 4:06 p.m., Bill Gottesman wrote:
The side of the trapezoid between12:00 and 1:00 skews to the 1:00 line 
- I have doubts that it was intended to track to the origin.  Whatever 
that means.


Well spotted.

On a copy of the dial face, I drew in the hour lines extended back 
towards the centre. Most of them convert at a point consistent with the 
knife-edge style that can be seen on the gnomon; likewise the hour lines 
for the hours closest to noon are slightly offset in a way that would be 
expected from the secondary styles created by the bevelled edges of the 
wide gnomon.


So, the dial was crafted quite precisely. The sides of the grey area 
don't match that precision, which supports your suggestion that it is a 
repair.


Cheers,

Steve

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Re: No more leap seconds!

[fabio.sav...@nonvedolora.it]

Dear all, I have never commented on this topic, I do it now with a proposal.

- The leap second takes into account a sort of 'noise', unpredictable 
before, for small variations in the speed of the Earth's rotation.
Anyway, over the millennia this speed will decrease, so the leap second 
is not enough but the 'physical' second will deviate from the 
'astronomical' one.
The physical one is necessary to measure the astronomical one and they 
are two different things despite the attempts of recent centuries to 
make them equivalent


- Martian days have a different second, residents will use the physical 
second as unit of measurement for their scientific instrument but they 
will want to live a 24-hour day (in any case full hours) with an 
astronomical second significantly different from the physical one.


- At the end of the 18th century the meter was calibrated as 1/1 of 
the distance between the equator and the pole, it was later found that 
the measurement is a few kilometers more and also changes from one 
meridian to another, not to mention the equator.
This did not change the unit of measurement and did not impose a wrong 
measurement of the Earth. It is accepted that the meter has an 
autonomous definition distinct from the geographic measurements of the 
planet.


In my opinion the problem is in the name: the 'second' is a name that 
derives from a fraction of the day while the physical second is a unit 
of measurement that is still unnamed.
If the physical second had a definition, it would help put an end once 
and for all between the demands of scientific measurement and the rhythm 
of a planet's days.
The gnomonists are the most focused community on the history of time for 
which I am launching a proposal:
help the scientific world to find a definition for the physical second, 
giving it a separate identity from the local astronomical second (Earth, 
Mars, etc.).
This forum could be the place to put forward some shared proposal and 
start using it.
It does not matter if the scientific community wants to change it, it 
would still be a success to have established that the physical second 
has a different name and identity from our dear old terrestrial second. 
That of clocks and sundials, and of our terrestrial life.


Long live the second, ciao Fabio


Il 21/11/2022 17:39, Steve Lelievre ha scritto:



Ah, the joys of Listservs and email software. My participation 
sometimes gets of of step too: occasionally, original posts reach me 
after other people's replies.


Perhaps it wouldn't be a problem if all the world's computers were 
exactly synchronized... perhaps they could use atomic clocks for that 
  ;-)


Cheers,

Steve


On 2022-11-21 12:04 a.m., John Pickard wrote:


Sorry Steve,

I sent my post before seeing yours.

--
Cheers, John.

Dr John Pickard.



---
https://lists.uni-koeln.de/mailman/listinfo/sundial


--
Fabio Savian
fabio.sav...@nonvedolora.it
www.nonvedolora.eu
Paderno Dugnano, Milano, Italy
45° 34' 9'' N, 9° 9' 54'' E, UTC +1 (DST +2)
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

RE: No more leap seconds!

[R. Hooijenga via sundial]

Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die
eigentliche Nachricht steht dadurch in einem Anhang.

This message was wrapped to be DMARC compliant. The actual message
text is therefore in an attachment.--- Begin Message ---
Didn't we have the same problem with the year, some centuries ago?

Is it what it is. The earth is slower than our atomic clock, and so at some
point, you will have to adjust - if you want noon to fall anywhere near
noon, that is.

 

Now people will complain about a leap second every few years (too often!),
likewise, they will complain about a leap minute very century (too big!).

If something is a fact of nature, people will complain about it and demand
it go away. It won't, so they complain more, and louder. It won't help, but
that only makes them be more right - everyone happy.

 

For my part, I don't care if they wait until it's a full year they must
adjust. I will just be amused by the hullaballoo that will cause when the
time comes - if I live to see it; it's a fairly big adjustment.

 

Rudolf 

52-30N 4-40E

--- End Message ---
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: No more leap seconds!

[Steve Lelievre]

Ah, the joys of Listservs and email software. My participation sometimes 
gets of of step too: occasionally, original posts reach me after other 
people's replies.


Perhaps it wouldn't be a problem if all the world's computers were 
exactly synchronized... perhaps they could use atomic clocks for that   ;-)


Cheers,

Steve


On 2022-11-21 12:04 a.m., John Pickard wrote:


Sorry Steve,

I sent my post before seeing yours.

--
Cheers, John.

Dr John Pickard.
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: No more leap seconds!

[John Goodman via sundial]

Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die
eigentliche Nachricht steht dadurch in einem Anhang.

This message was wrapped to be DMARC compliant. The actual message
text is therefore in an attachment.--- Begin Message ---
It’s hard to conclude that ‘“nothing will change” for the public’, when there’s 
a proposal for ‘a “kind of smear”, in which the last minute of the day takes 
two minutes.’

> Date: Sun, 20 Nov 2022 19:56:23 -0800
> From: Steve Lelievre 
> To: Sundial List 
> Subject: No more leap seconds!
> 
> Apparently the Powers That Be have officially decided that Clock Time is 
> right and Solar Time is wrong.
> 
> Or to put it another way, the International Bureau of Weights and 
> Measures has voted to stop using Leap Seconds by by 2035.
> 
> However, an IBWM representative said "the connection between UTC and the 
> rotation of the Earth is not lost [...] Nothing will change [for the public]" 
> which apparently means we'll have less frequent adjustments instead (leap 
> minutes?).
> 
> https://phys.org/news/2022-11-global-timekeepers-vote-scrap.html
> 
> Steve
> 
> --
> Date: Mon, 21 Nov 2022 18:59:44 +1100
> From: John Pickard 
> 
> Good evening,
> 
> I doubt it will affect dials very much, especially the EoT, ...
> 
> https://www.theguardian.com/world/2022/nov/18/do-not-adjust-your-clock-scientists-call-time-on-the-leap-second
> 
> -- 
> Cheers, John.
> 
> Dr John Pickard.
--- End Message ---
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: No more leap seconds!

[John Pickard]

Sorry Steve,

I sent my post before seeing yours.

--
Cheers, John.

Dr John Pickard.


On 21-November-2022 14:56, Steve Lelievre wrote:


Apparently the Powers That Be have officially decided that Clock Time 
is right and Solar Time is wrong.


Or to put it another way, the International Bureau of Weights and 
Measures has voted to stop using Leap Seconds by by 2035.


However, an IBWM representative said "the connection between UTC and 
the rotation of the Earth is not lost [...] Nothing will change [for 
the public]" which apparently means we'll have less frequent 
adjustments instead (leap minutes?).


https://phys.org/news/2022-11-global-timekeepers-vote-scrap.html

Steve


---
https://lists.uni-koeln.de/mailman/listinfo/sundial
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: sundial Digest, Vol 200, Issue 6

[Polluxsterrenwacht]

For sundials Amsterdam see: www.zonnewijzers-nederland.nl 

Clear skies,  
Gerard van den Braak
www.sterrenwacht.eu
www.zonnewijzers-nederland.nl

> Op 17 nov. 2022 om 11:04 heeft sundial-requ...@uni-koeln.de het volgende 
> geschreven:
> 
> Send sundial mailing list submissions to
>sundial@uni-koeln.de
> 
> To subscribe or unsubscribe via the World Wide Web, visit
>https://lists.uni-koeln.de/mailman/listinfo/sundial
> or, via email, send a message with subject or body 'help' to
>sundial-requ...@uni-koeln.de
> 
> You can reach the person managing the list at
>sundial-ow...@uni-koeln.de
> 
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of sundial digest..."
> 
> 
> Today's Topics:
> 
>   1. I'm off on a quick package tour with a day off in Amsterdam.
>  I'm planning on visiting the Sundial Nieuwe Kerk (
>  
> https://www.waymarking.com/waymarks/WMXFZZ_Sundial_Nieuwe_Kerk_Amsterdam_NH_NL
>  
>  ). I'm curious about the 2006 NASS Sawyer Dialing Prize "Spectra
>  Sundial" described here (
>  
> https://www.artisanindustrials.com/world-of-sundials/spectra-sundial-amsterdam-netherlands.html
>  
>  ) but not confident of the location (Google maps marks these
>  coordinates in a canal). I was sad to discover the Amsterdam
>  Sundial Trail, once available here:
>  http://www.fransmaes.nl/zonnewijzers/welcome-e.htm is no longer
>  available. I'm staying downtown near the Rijksmuseum and will be
>  exploring the area. I will continue my internet search for for
>  sundials in the area but would be grateful for any suggestions.
>  I'm not much of a photographer, but will be taking photos and
>  report back my discoveries to this list (if that's not
>  inappropriate). Thank you for your consideration. I'll also be
>  traveling through Brussels (Jeffery Brewer)
>   2. Coordinate transformer (Dan-George Uza)
> 
> 
> --
> 
> Message: 1
> Date: Wed, 16 Nov 2022 10:39:26 -0800
> From: Jeffery Brewer 
> To: sundial@uni-koeln.de
> Subject: I'm off on a quick package tour with a day off in Amsterdam.
>I'm planning on visiting the Sundial Nieuwe Kerk (
>
> https://www.waymarking.com/waymarks/WMXFZZ_Sundial_Nieuwe_Kerk_Amsterdam_NH_NL
>  
>). I'm curious about the 2006 NASS Sawyer Dialing Prize "Spectra
>Sundial" described here (
>
> https://www.artisanindustrials.com/world-of-sundials/spectra-sundial-amsterdam-netherlands.html
>  
>) but not confident of the location (Google maps marks these
>coordinates in a canal). I was sad to discover the Amsterdam Sundial
>Trail, once available here:
>http://www.fransmaes.nl/zonnewijzers/welcome-e.htm is no longer
>available. I'm staying downtown near the Rijksmuseum and will be
>exploring the area. I will continue my internet search for for
>sundials in the area but would be grateful for any suggestions. I'm
>not much of a photographer, but will be taking photos and report back
>my discoveries to this list (if that's not inappropriate). Thank you
>for your consideration. I'll also be traveling through Brussels
> Message-ID:
>
> Content-Type: text/plain; charset="utf-8"
> 
> 
> -- next part --
> An HTML attachment was scrubbed...
> URL: 
> <https://lists.uni-koeln.de/mailman/private/sundial/attachments/20221116/b9cd68a4/attachment-0001.html>
> 
> --
> 
> Message: 2
> Date: Thu, 17 Nov 2022 12:04:14 +0200
> From: Dan-George Uza 
> To: Sundial List 
> Subject: Coordinate transformer
> Message-ID:
>
> Content-Type: text/plain; charset="utf-8"
> 
> Hello,
> 
> I found this online and I think it can be used also for telling time if you
> know the solar declination and the Sun's altitude.
> 
> Best wishes,
> 
> -- 
> Dan-George Uza
> -- next part --
> An HTML attachment was scrubbed...
> URL: 
> <https://lists.uni-koeln.de/mailman/private/sundial/attachments/20221117/8fa70aa0/attachment.html>
> -- next part --
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> Name: text.jpg
> Type: image/jpeg
> Size: 147927 bytes
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> URL: 
> <https://lists.uni-koeln.de/mailman/private/sundial/attachments/20221117/8fa70aa0/attachment.jpg>
> -- next part --
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> Desc: not a

Re: Vertical stereographic sundial

[mlose]

Hi Peter,If we set a horizontal stereographic dial at 55deg N and move it to 
35deg S, not changing its position in space, it becomes a vertical there.What 
changes is the position of the observer on the globe - not the sundial.The 
difference is that in a vertical position at 35deg S the upper halve of the 
original dial is useless, as Sun rays are cut by the horizon in Adelaide.But 
you can make the upper halve usefull in a simple way, by folding the sundial 
along the horizon line !By doing it, you get a second (south-oriented) face for 
your dial and preserve the all year functionality of the original 55deg 
location !But you must remember to extend the gnomon rod to the south side !The 
co-latitude similarity brought me an idea of establishing gnomonic twin cities, 
for which one sundial would work !As a resident of the latitude of 51deg North 
I'm looking for offers from lat. 39deg South !As the winter is coming in North 
hemisphere, I will kindly accept offers for a courtsey visit to 39deg South 
with a stereographic sundial at hand ready for experiments !Regards,Maciej 
LoseOd: "Peter Mayer" a1000...@adelaide.edu.auDo: ml...@interia.pl; 
peter.ma...@adelaide.edu.au; Wysłane: 2:12 Piątek 2022-11-04Temat: Re: Vertical 
stereographic sundial


  
  
Hi Maciej,
Here's a puzzle for you
and others on the list. Does the usual 'co-latitude' rule for
other plane sundials hold for Oughtred/stereograph dials? I've
tried a quick empirical experiment using Orologi Solari
creating a vertical stereograph for my latitude (35S) and a
horizontal for the co-latitude (55N). The two seem identical
(except for the numbering of hours). It's not a 'geometric
proof' but it seems entirely reasonable.
I had meant to add in
my earlier post that a few years ago I, too, wrote a DeltaCad
macro for an Oughtred dial. Unlike the elegant trigonometry used
by Valentin, I tried to replicate the protractor, compass and
straightedge methods in a traditional construction. Once it
worked for my Southern Hemisphere location, I stopped working on
it, so it is really a beta version, but I'm happy to forward it
to anyone who is interested.
best wishes,
Peter

On 2/11/2022 5:25:29, ml...@interia.pl
  wrote:


  
  

 CAUTION:
  External email. Only click on links or open attachments
  from trusted senders. 

  


  Hi Peter,
  Thank You for the links.
  My plea concerned vertical stereographic sundials - not
the horizontal ones. I'm aware that there are a number of
programs to construct horizontal sterographic dials.
  Helmut Sonderegger kindly proposed to include vertical
ones in Sonne, when he finds a time for it, and the info form
Valentin was that for the vertical plane he actually worked on a
spider dial, which is most interesting but of different type
than stereographic.
  But I must admit that I was unaware of construction
possibilty of vertical stereographic dials (under the name
"vertical astrolabe") in Oroligi Solari.
  Though, the program doesn't give any limits for the
gnomon - which in this type of instruments is no longer that 1/2
the dial's radius, as discussed in my paper, irrespective of
walls' declination, latitude and sundial's plane inclination. It
doesn't also give options for inclining dials. So there is some
space for it to be upgraded making this very nice typology more
approachable for sundial makers. Also, derivatives like the
four-sided, "gnomon-less" stereographic vertical sundial could
be included.
  Drawing by hand (with CAD) is obviously time consuming,
but it allows for understanding of geometrical relations behind
and allows for inclusion of elements not available in the custom
software. So not being a skilful programmer, I will rather stay
with that ! But for the sundial makers it is obviously easier to
use a software.
  Regards,
  Maciej
  
Od: "Peter Mayer" a1000...@adelaide.edu.au
Do: sundial@uni-koeln.de; ml...@interia.pl; 
Wysłane: 5:58 Poniedziałek 2022-10-31
Temat: Re: Vertical stereographic sundial 

  
  

  Hi Maciej,
  Thanks for your recent post. Since no one seems to have
replied to your plea in the final paragraph for software to
draw a stereographic/Oughtred dial, here are some existing
open software options:
  * Gian Casalegna's Orologi Solari will draw one:
azimuth: horizontal/vertical: astrolabe
  *Helmut Sondereggers' Sonne will draw at least a horizontal

Re: Vertical stereographic sundial

[Peter Mayer]

Hi Maciej,

Here's a puzzle for you and others on the list. Does the usual 
'co-latitude' rule for other plane sundials hold for 
Oughtred/stereograph dials? I've tried a quick empirical experiment 
using _Orologi Solari_ creating a vertical stereograph for my latitude 
(35S) and a horizontal for the co-latitude (55N). The two seem identical 
(except for the numbering of hours). It's not a 'geometric proof' but it 
seems entirely reasonable.


I had meant to add in my earlier post that a few years ago I, too, wrote 
a DeltaCad macro for an Oughtred dial. Unlike the elegant trigonometry 
used by Valentin, I tried to replicate the protractor, compass and 
straightedge methods in a traditional construction. Once it worked for 
my Southern Hemisphere location, I stopped working on it, so it is 
really a beta version, but I'm happy to forward it to anyone who is 
interested.


best wishes,

Peter

On 2/11/2022 5:25:29, ml...@interia.pl wrote:

*
CAUTION: External email. Only click on links or open attachments from 
trusted senders.

*


Hi Peter,

Thank You for the links.

My plea concerned vertical stereographic sundials - not the horizontal 
ones. I'm aware that there are a number of programs to construct 
horizontal sterographic dials.


Helmut Sonderegger kindly proposed to include vertical ones in Sonne, 
when he finds a time for it, and the info form Valentin was that for 
the vertical plane he actually worked on a spider dial, which is most 
interesting but of different type than stereographic.


But I must admit that I was unaware of construction possibilty of 
vertical stereographic dials (under the name "vertical astrolabe") in 
Oroligi Solari.


Though, the program doesn't give any limits for the gnomon - which in 
this type of instruments is no longer that 1/2 the dial's radius, as 
discussed in my paper, irrespective of walls' declination, latitude 
and sundial's plane inclination. It doesn't also give options for 
inclining dials. So there is some space for it to be upgraded making 
this very nice typology more approachable for sundial makers. Also, 
derivatives like the four-sided, "gnomon-less" stereographic vertical 
sundial could be included.


Drawing by hand (with CAD) is obviously time consuming, but it allows 
for understanding of geometrical relations behind and allows for 
inclusion of elements not available in the custom software. So not 
being a skilful programmer, I will rather stay with that ! But for the 
sundial makers it is obviously easier to use a software.


Regards,

Maciej


Od: "Peter Mayer" 
Do: sundial@uni-koeln.de; ml...@interia.pl;
Wysłane: 5:58 Poniedziałek 2022-10-31
Temat: Re: Vertical stereographic sundial

Hi Maciej,

Thanks for your recent post. Since no one seems to have replied to
your plea in the final paragraph for software to draw a
stereographic/Oughtred dial, here are some existing open software
options:

* Gian Casalegna's _Orologi Solari_ will draw one: azimuth:
horizontal/vertical: astrolabe

*Helmut Sondereggers' Sonne will draw at least a horizontal
stereograph: Azimuthal: Sun Altitude

* Valentin Hristov has written some elegant code for DeltaCad
:www.math.bas.bg/complan/valhrist/az-ht.bas
<http://www.math.bas.bg/complan/valhrist/az-ht.bas>
[When I tried to re-run it a few minutes ago, it now seems to be
stuck in a loop which I haven't had time to debug. I've attached
an example which I created about 4 years ago].

So: no need to create a stereograph by hand!

best wishes,

Peter


On 27/10/2022 4:02:34, ml...@interia.pl wrote:

CAUTION: External email. Only click on links or open attachments
from trusted senders.

Dear All,

As proven in a separate tread on "Sun elevation tool/
horizontoscope", stereographic projection is
a fascinating geometric construction with great potential in
gnomonics.

During last year I explored the idea of vertical stereographic
sundial and it resulted in
a paper describing several stereographic sundial types:

- vertical stereographic sundial, for walls of any declination
and for any latitude,
- four-sided stereographic vertical sundial, attractive for its
“gnomon-less” form,
- double – stereographic & polar – vertical sundial for walls of
any declination, a vertical reference to Oughtred’s horizontal
design,
- folded pocket, double stereographic & polar – vertical sundial
- inclined, proclined and polyhedral stereographic sundials

The paper can be downloaded free of charge from Cursiva
publishers website:


http://cursiva.pl/e-ksiegarnia/vertical-stereographic-sundial-properties-construction-and-related-instruments/

<http://cursiva.pl/e-ksiegarnia/vertical-stereographic-sundial-properties-construction-and-related-in

Re: Metal gnomons

[Michael Ossipoff]

What’s wrong with brass changing its color with weathering? Isn’t that part
of the appeal of brass?

On Sat, Apr 30, 2022 at 8:56 AM Dan-George Uza 
wrote:

> Hi,
>
> Iron rusts and brass changes color, but what about different metals used
> as gnomons, pros & cons?
>
> What would be the appropriate choice of material for a replica of an 18th
> century cubical multiple sundial? It should ideally come as an industrial
> sheet ready for cutting and also not stain the limestone face.
>
> I like the metal in the attached photo (Sundial Atlas CH 000247). Do you
> know what it is?
>
> Thanks,
>
> Dan Uza
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Vertical stereographic sundial

[mlose]

Hi Peter,Thank You for the links.My plea concerned vertical stereographic 
sundials - not the horizontal ones. I'm aware that there are a number of 
programs to construct horizontal sterographic dials.Helmut Sonderegger kindly 
proposed to include vertical ones in Sonne, when he finds a time for it, and 
the info form Valentin was that for the vertical plane he actually worked on a 
spider dial, which is most interesting but of different type than 
stereographic.But I must admit that I was unaware of construction possibilty of 
vertical stereographic dials (under the name "vertical astrolabe") in Oroligi 
Solari.Though, the program doesn't give any limits for the gnomon - which in 
this type of instruments is no longer that 1/2 the dial's radius, as discussed 
in my paper, irrespective of walls' declination, latitude and sundial's plane 
inclination. It doesn't also give options for inclining dials. So there is some 
space for it to be upgraded making this very nice typology more approachable 
for sundial makers. Also, derivatives like the four-sided, "gnomon-less" 
stereographic vertical sundial could be included.Drawing by hand (with CAD) is 
obviously time consuming, but it allows for understanding of geometrical 
relations behind and allows for inclusion of elements not available in the 
custom software. So not being a skilful programmer, I will rather stay with 
that ! But for the sundial makers it is obviously easier to use a 
software.Regards,MaciejOd: "Peter Mayer" 
a1000...@adelaide.edu.auDo: sundial@uni-koeln.de; ml...@interia.pl; 
Wysłane: 5:58 Poniedziałek 2022-10-31Temat: Re: Vertical stereographic sundial


  
  
Hi Maciej,
Thanks for your recent post. Since no one seems to have replied
  to your plea in the final paragraph for software to draw a
  stereographic/Oughtred dial, here are some existing open software
  options:
* Gian Casalegna's Orologi Solari will draw one: azimuth:
  horizontal/vertical: astrolabe
*Helmut Sondereggers' Sonne will draw at least a horizontal
  stereograph: Azimuthal: Sun Altitude
* Valentin Hristov has written some elegant code for DeltaCad
  :www.math.bas.bg/complan/valhrist/az-ht.bas [When I tried to
  re-run it a few minutes ago, it now seems to be stuck in a loop
  which I haven't had time to debug. I've attached an example which
  I created about 4 years ago].
So: no need to create a stereograph by hand!
best wishes,
Peter



On 27/10/2022 4:02:34, ml...@interia.pl
  wrote:


  
  CAUTION: External email. Only click on links or open attachments
  from trusted senders.
  
  Dear All,
  
  As proven in a separate tread on "Sun elevation tool/
  horizontoscope", stereographic projection is 
  a fascinating geometric construction with great potential in
  gnomonics.
  
  During last year I explored the idea of vertical stereographic
  sundial and it resulted in 
  a paper describing several stereographic sundial types:
  
  - vertical stereographic sundial, for walls of any declination and
  for any latitude,
  - four-sided stereographic vertical sundial, attractive for its
  “gnomon-less” form,
  - double – stereographic  polar – vertical sundial for walls
  of any declination, a vertical reference to Oughtred’s horizontal
  design,
  - folded pocket, double stereographic  polar – vertical
  sundial
  - inclined, proclined and polyhedral stereographic sundials
  
  The paper can be downloaded free of charge from Cursiva publishers
  website:
  
  
http://cursiva.pl/e-ksiegarnia/vertical-stereographic-sundial-properties-construction-and-related-instruments/
  
  or from Academia.edu website:
  
  
https://www.academia.edu/88820719/Vertical_stereographic_sundial_Properties_construction_and_related_instruments
  
  Have fun with it !
  
  Vertical stereographic sundials offer plenty of possibilities for
  sundial makers 
  and I believe might be a very interesting addition to existing
  sundial types.
  
  As the geometric construction of vertical stereographic sundials
  with CAD software is time-consuming, 
  it would be great to include it in existing sundial design
  software. 
  I kindly ask sundial list members running such software, please
  consider it !
  
  Regards,
  
  Maciej Lose
  
  ---
  https://lists.uni-koeln.de/mailman/listinfo/sundial
  
  

-- 
---
Peter Mayer
Department of Politics  International Relations (POLIR)
School of Social Sciences
http://www.arts.adelaide.edu.au/polis/
The University of Adelaide, AUSTRALIA 5005
Ph : +61 8 8313 5609
Fax : +61 8 8313 3443
e-mail: peter.ma...@adela

Re: Comments on Peter's mail

[Bill Gottesman]

Hello Valentin,

My version of DeltaCad (10.0.0 for Mac) will not run .bas macros, only
.scpt macros.
Do you know if there is a way to get your macros to run on this version of
deltacad?

-Best, Bill

On Mon, Oct 31, 2022 at 4:32 AM Valentin Hristov 
wrote:

> Greetings from Bulgaria to the sundial community!
> Thank you, Peter, for mentioning my DeltaCad macro
> www.math.bas.bg/complan/valhrist/az-ht.bas
> I give here only the link since usually the servers reject files with
> extension .bas. You have to open them in a new page, mark the whole text,
> copy to the clipboard, and paste into some text editor, saving the file
> with extension .bas. Then run DeltaCad - Macro - RunMacro - choose the
> saved file *.bas.
> Unfortunately, my polar variant is only horizontal (azimuth and height),
> but can be used as an effective sundial as shown on the attached picture.
> The edge of a tea bags box is the vertical gnomon!
> Many of my DeltaCad macros can be found on my page
> My Stuff - Valentin Hristov (bas.bg)
> 
> as well with many details on Carl Sabanski's page
> The Sundial Primer - DeltaCad Sundial Macros - Valentin Hristov - Polar
> Box Sundial (mysundial.ca)
> 
> Let there be more sunshine on your sundials!
> Valentin Hristov
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Paris sundial

[Bill Gottesman]

Is this real or a concept? The shadows don’t move in the rest of the image.
- Bill

On Sun, Oct 30, 2022 at 7:14 AM Alexei Pace  wrote:

> Interesting one in Rue Montmartre
> https://www.instagram.com/reel/Cj0hS2JIPQV/?igshid=YmMyMTA2M2Y=
>
> On Wed, Oct 26, 2022, 11:58 Werner Riegler  wrote:
>
>> Dear John,
>>
>> I know this object as “Horizontoscope".
>> http://www.horizontoscop.com/eng/index_eng.html
>>
>> I bought one recently after reading about it in one of Helmut
>> Sonderegger’s articles, where he gives the math of it.
>>
>> https://www.herzog-forsttechnik.ch/wp-content/uploads/2022/08/Sonnenkompass_Flyer-2022.pdf
>>
>> It’s quite interesting how the hyperbolic surface makes the image
>> independent of the height between the observing eye and the device.
>>
>> There is a german wikipedia entry.
>> https://de.wikipedia.org/wiki/Horizontoskop
>>
>> Maybe someone from the sundial list can produce an english entry with the
>> theory. It’s a nice device !
>>
>> best regards
>> Werner
>>
>>
>>
>>
>>
>> On 26 Oct 2022, at 02:45, John Pickard  wrote:
>>
>> Good morning,
>>
>> Has anyone come across this dial-related device?
>>
>>
>> https://picclick.co.uk/ARCHITECT-TOOL-Window-SUNLIGHT-SUN-ELEVATION-Enraf-144741549298.html
>>
>> Cheers, John.
>>
>> Dr John Pickard.
>>
>> ---
>> https://lists.uni-koeln.de/mailman/listinfo/sundial
>>
>>
>> ---
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>>
>> ---
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>
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Re: Calculation & Estimation of Solar ecliptic-longitude & EqT

[Michael Ossipoff]

I forgot to mention that the amount by which the mean sun gains on the
actual sun in R.A. is eastward, in the opposite direction to the Sun's
diurnal motion.

...& so, the amount by which the mean Sun gains on the actual Sun in
hour-angle. is the negative of the amount by which it gains on the actual
Sun in R.A.

So when the mean Sun's R.A. gain over the actual Sun during the period of
interest is determined, & multiplied by 4, you must change the sign of that
difference to get the EqT.



On Sat, Oct 29, 2022 at 8:48 PM Michael Ossipoff 
wrote:

> There was something posted recently about how to calculate the Solar
> ecliptic-longitude, & thereby the Equation of Time (EqT).
>
> .
>
> (I should emphasize, that, when the Solar ecliptic-longitude is determined
> as described below, of course the Solar declination can be gotten from it
> by the method that we discussed earlier.)
>
> .
>
> It used a formula derived by solving our Solar orbit.
>
> .
>
> With matters like that, it’s of interest how the formulas are derived.
>
> .
>
> I once solved the orbital problem. It wasn’t for planetary-orbits.  I
> wanted to find out how far the fastest rifle bullet (4110 fps, from
> something I’d read 20 years previous) could go, on the moon.
>
> .
>
> If the ground were flat, with uniform gravitational-field, I get about 600
> miles. But, for such a long range, those assumptions aren’t good enough.
> It’s necessary to do it as an orbital problem.   …an orbit about the
> moon’s center, that intersects the moon’s surface.
>
> .
>
> (The answer that I got was just a bit more than 800 miles. It might have
> been about 820 miles.)
>
> .
>
> For me, by far the most straightforward solution-method was by
> conservation-laws.   …as opposed to the solution-method that uses
> dynamics.
>
> .
>
> Well one of the conservation-laws—conservation of angular-momentum, is
> proved via dynamics. By far the simplest & most straightforward way to do
> that is in Lagrangian dynamics.
>
> .
>
> The conservation-laws solution involves an integral that can be solved in
> closed form.  (Numerical-integration isn’t necessary.)
>
> .
>
> And, as is so often the case, it’s one of those integrations that requires
> trial-&-error to find the Integrand’s antiderivative.
>
> .
>
> There are several methods for converting the problem of integrating one
> function, to a problem of integrating a different one.  So you apply
> whichever of those methods seems most promising, & if it seems to give you
> a new integration problem that looks simpler or more promising, then you
> apply one of the conversion methods to that new integral…& keep doing so
> till it leads to an expression whose integral is known.
>
> .
>
> So the integration involved a bit of trial & error, but was solvable in
> closed form.  (…as opposed to requiring a numerical approximation.)
>
> .
>
> But, if you’re on a desert island, & need the EqT for
> position-determination, or for some reason you need mean time or standard
> time from your sundial, then to use a solution of the Earth’s orbit, you’d
> have to:
>
> .
>
> 1. Solve our orbit to derive the formulas.
>
> .
>
> OR
>
> .
>
> 2. Have a piece of paper on which the formula is written
>
> .
>
> OR
>
> .
>
> 3.  Have been solving orbits so regularly & recently that you don’t need
> to look up the needed formulas.
>
> .
>
> And another problem is that you’d need the initial conditions at some
> recent epoch.  That too would have to be looked-up.   …again, unless
> you’ve been doing the problem so much lately that you know the
> initial-conditions.
>
> .
>
> ….&, if you’re going to carry around a piece of paper with the
> orbital-solution formula & the initial-conditions…well then, why not just
> carry a piece of paper with the EqT & Solar declination for each day of the
> current year (…& maybe the next few years if you might be on your desert
> island or at sea for a few years)?
>
> .
>
> So it would be desirable to have an easier approximation for the EqT.
>
> .
>
> I’ll suggest one.
>
> .
>
> The month-lengths of the ecliptic-month approximations in the Indian
> National Calendar can give you an estimate of the Solar ecliptic-longitude
> for any day, if you know the date of the nearest equinox (or even roughly
> if not exactly).
>
> .
>
> Start with a day known to have an EqT of zero.  September 1st & Christmas
> are such days.
>
> .
>
> The Indian National Calendar has 30-day & 31-day months.
>
> .
>
> Taurus thru Virgo have 31 days. The other months have 30 days.
>
> .
>
> Taurus  starts in April. Virgo starts in August.
>
> .
>
> So, Taurus & Virgo are the ecliptic months that start in a month that
> starts with “A”.
>
> .
>
> In a 31 day month, the average motion rate along the ecliptic is 30/31
> degrees per day.
>
> .
>
> In a 30 day month, the average motion rate along the ecliptic is 1 degree
> per day.
>
> .
>
> Start with a day known to have an EqT of zero.  September 1st & Christmas
> are two such days.
>
> .
>
> (There 

Re: Sun elevation tool

[Werner Riegler]

Dear John,

I know this object as “Horizontoscope".
http://www.horizontoscop.com/eng/index_eng.html

I bought one recently after reading about it in one of Helmut Sonderegger’s 
articles, where he gives the math of it.
https://www.herzog-forsttechnik.ch/wp-content/uploads/2022/08/Sonnenkompass_Flyer-2022.pdf

It’s quite interesting how the hyperbolic surface makes the image independent 
of the height between the observing eye and the device.

There is a german wikipedia entry.
https://de.wikipedia.org/wiki/Horizontoskop

Maybe someone from the sundial list can produce an english entry with the 
theory. It’s a nice device !

best regards
Werner





On 26 Oct 2022, at 02:45, John Pickard 
mailto:john.pick...@bigpond.com>> wrote:


Good morning,

Has anyone come across this dial-related device?

https://picclick.co.uk/ARCHITECT-TOOL-Window-SUNLIGHT-SUN-ELEVATION-Enraf-144741549298.html

Cheers, John.

Dr John Pickard.

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Re: Sun elevation tool

[John Lynes]

There is a description of the TNO "jellyfish", as it was affectionally
known, in a paper by J van der Eijk, "Instrumentation for Solar Studies",
in the *Proceedings of the CIE Intersessional Conference on Sunlight in
Buildings*, Bouwcentrum International, Rotterdam 1967, and reprinted as
Publication 241 of the Research Institute for Public Health Engineering
TNO, Delft.
A more accurate instrument on similar lines was Gunnar
Pleijel's "Globoscope", a convex paraboloid whose mirrored surface
reflected a stereographic projection of the solar orbit and its
surroundings. (G Pleijel, "The Computation of Natural Radiation in
Architecture and Town Planning", Bulletin 25, Statens Namnd for
Byggnadsforskning, Stockholm 1954).
A cheaper Globoscope, based on a vehicle hub cap, was described by
Professor P F O'Brien, of the University of California, Los Angeles, in the
journal *Illuminating Engineering. * I don't have the reference handy.
John Lynes

On Wed, 26 Oct 2022 at 01:46, John Pickard  wrote:

> Good morning,
>
> Has anyone come across this dial-related device?
>
>
> https://picclick.co.uk/ARCHITECT-TOOL-Window-SUNLIGHT-SUN-ELEVATION-Enraf-144741549298.html
>
> Cheers, John.
>
> Dr John Pickard.
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
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Re: How to turn ecliptic longitude into solar declination?

[Michael Ossipoff]

Okay, that’s good to hear. …& thanks clearing it up.

On Sun, Oct 16, 2022 at 3:54 PM Steve Lelievre <
steve.lelievre.can...@gmail.com> wrote:

> Michael,
>
> On 2022-10-16 1:40 p.m., Michael Ossipoff wrote:
> > Thank you for mentioning that I answered Steve's question.
> > ...something not acknowledged by Steve for some reason.
> >
> Please be assured that no slight was intended. Thank you for taking the
> time to reply to my question.
>
> I did not acknowledge your response because I had not seen it. My email
> software treated your messages as spam so I didn't see them until
> Frank's message prompted me to check the junk folder. Just as soon as I
> figure out the applicable setting, I'll change it.
>
> Steve
>
>
>
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Re: How to turn ecliptic longitude into solar declination?

[Steve Lelievre]

Michael,

On 2022-10-16 1:40 p.m., Michael Ossipoff wrote:
Thank you for mentioning that I answered Steve's question.   
...something not acknowledged by Steve for some reason.


Please be assured that no slight was intended. Thank you for taking the 
time to reply to my question.


I did not acknowledge your response because I had not seen it. My email 
software treated your messages as spam so I didn't see them until 
Frank's message prompted me to check the junk folder. Just as soon as I 
figure out the applicable setting, I'll change it.


Steve


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Re: How to turn ecliptic longitude into solar declination?

[Michael Ossipoff]

Frank--

Thank you for mentioning that I answered Steve's question.   ...something
not acknowledged by Steve for some reason.

I didn't notice that when I first read your post. Thanks for setting the
record straight !

So, to the list I just want to clarify that, when Steve asked how to
determine declination from ecliptic-longitude, I was the first to answer
his question, when I gave the following instruction:

"Multiply the sine of the ecliptic-longitude by the sine of the obliquity,
& then take the inverse-sine of the result."

October 16th
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Re: How to turn ecliptic longitude into solar declination?

[Michael Ossipoff]

[quote]
At the moment we are in Vintagarious, the
first month, and you will see that each
day has the symbol for Aries.
[/quote]

Then you have an error, because Vendemiaire doesn't roughly approximate
Aries. Vendemiaire
roughly approximates Libra.

As for the nature of the French Republican Calendar's rough approximation
of the ecliptic-months, due to its piling up its excess 5 or 6 says all at
the end of the year, IL amply covered that in earlier posts.  The Indian
National Calendar does a much better job, when it gives 31 days to Taurus
thru Virgo.

The Indian National Calendar isn't a fixed calendar.  No blank days & no
periodic-error-increase due to a leapweek.
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Re: How to turn ecliptic longitude into solar declination?

[Frank King]

Dear Steve,

Michael, Werner and Fabio have provided some
excellent responses to your question.

If you are ONLY interested in relating three
ANGLES - solar longitude, solar declination
and the obliquity - then this relationship is
indeed all you need:

  sin(lambda).sin(obliquity) = sin(declination)

Importantly, the cusps (starts) of the 12
Zodiacal months are DEFINED as being at
30-degree intervals round the ecliptic.
If you wish to use one-third months, then
using 10=degree intervals is the right thing
to do.

[ASIDE: I deliberately overlook numerous little
details such as 12x30 not being quite 360 degrees
because the sun doesn't QUITE get back to where
it started, but you can usually ignore that
unless you want to discuss fine details with
Werner :-)]

As every diallist knows, equal angles do not
generally translate into equal intervals of
time.  The sun doesn't travel round the
ecliptic at a uniform speed.

Fabio's ring illustrates this beautifully
BUT Fabio's French Republican Calendar
also tells you about this, not just on the
inside front cover but also...

By looking at the information provided
for each day, you can do some simple
investigation as to how the lengths of
the Zodiacal months vary...

At the moment we are in Vintagarious, the
first month, and you will see that each
day has the symbol for Aries.

Next month is Fogarious and you will see
that each day has the symbol for Scorpio.

The following month is Frostaious and you
will see that each day has the symbol for
Sagittarius.

This seems too good to be true.  Seemingly
the 30-day months are precisely in sync
with the Zodiacal months.  Sadly this isn't
quite the case because...

The following month is Snowous and only
the first 29 days shows the symbol for
Capricorn.  We are at our closest to the
sun here and actually cover more than
one degree a day.  You will see Day 30
shows the symbol for Aquarius.

The Calendar is running one day slow!

Here is a table of the crude end-of-month
errors in days slow (-) and days fast (+):

 Vintagearious   0
 Fogarious   0
 Frostarious 0
 Snowous-1
 Rainous-1
 Windous-1
 Buddal -1
 Floweral0
 Meadowal   +2
 Reapidor   +3
 Heatidory  +4
 Fruitidor  +5

I find it astonishing that it is only in
the last four months that we end the month
more than a day fast or slow.

Of course we end the 12-month period five
days early which is why the calendar ends
with five (or six) Complementary Days.

This is a nice simple way of showing that
the angular rate of change in solar
longitude doesn't vary very much!

I find that the more I live with this
Calendar the more it grows on me :-)

You will find this too!

Very best wishes
Frank


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Re: How to turn ecliptic longitude into solar declination?

[Steve Lelievre]

My thanks go Werner for his detailed and helpful response to my 
question, and Fabio for his interesting comments on the astrolabe.


I learned some new things today, and it was nice to see a diagram of the 
offset circles on the back of the astrolabe. Clever.


Cheers,

Steve


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Re: How to turn ecliptic longitude into solar declination?

[Werner Riegler]

Dear Steven,

The relation of solar declination delta(t)  to ecliptic longitude lambda(t) 
delta(t) = ArcSin[Sin[23.44]*Sin[lambda[t]]

You are interested in the relation of solar declination to time since the 
equinox.

Your formula delta(t) = 23.44*Sin(t), with t being the time (in degrees) since 
the spring equinox, is mathematically the 'first order Taylor expansion in  
obliquity phi’ of the precise expression for the solar declination.
The difference of your formula to the accurate expression is around 0.9 degrees 
maximum.

The 'first order Taylor expansion in eccentricity ecc’ is
delta(t) = ArcSin[Sin[phi]*Sin[t]] + ecc * Sin[phi] * Sin[2*t] / Sqrt[1 - 
Sin[phi]^2*Sin[t]^2] 
which is accurate to 0.015 degrees. (phi=23.44 degrees)

It is a much better approximation because for a Taylor approximation the 
argument should be much smaller than unity. 
phi=2*Pi/360*23.44 = 0.41 is not so small, but ecc=0.0167 is very small ...

You could still approximate the above expression to 
delta(t) = ArcSin[Sin[phi]*Sin[t]] + ecc * Sin[phi] * Sin[2*t] 
which is accurate to 0.03 degrees, and it does take into account the 
eccentricity of the orbit.

Other approximations can quickly become more complicated than using directly 
the correct formulas.

The numbers are still in my head because I recently  discussed this point in 
the NASS293 article on the analemma (Eq. 19, Eq. 20).

cheers
Werner



> On 15 Oct 2022, at 01:56, Steve Lelievre  
> wrote:
> 
> Hi,
> 
> For a little project I did today, I needed the day's solar declination for 
> the start, one third gone, and two-thirds gone, of each zodiacal month (i.e. 
> approximately the 1st, 11th and 21st days of the zodiacal months).
> 
> I treated each of the required dates as a multiple of 10 degrees of ecliptic 
> longitude, took the sine and multiplied it by 23.44 (for solstitial solar 
> declination). At first glance, the calculation seems to have produced results 
> that are adequate for my purposes, but I've got a suspicion that it's not 
> quite right (because Earth's orbit is an ellipse, velocity varies, etc.)
> 
> My questions: How good or bad was my approximation? Is there a better 
> approximation/empirical formula, short of doing a complex calculation?
> 
> Cheers,
> 
> Steve
> 
> 
> 
> 
> 
> ---
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> 

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Re: How to turn ecliptic longitude into solar declination?

[Michael Ossipoff]

I emphasize that saying that each third of an ecliptic-month is 10 degrees
is not an approximation. An ecliptic-month is defined as exactly 1/3 of an
astronomical- quarter…1/3 by ecliptic-longitude, not by time or days.

An astronomical-quarter is the ecliptic interval between a solstice & an
equinox…90 degrees along the ecliptic.

On Fri, Oct 14, 2022 at 11:33 PM Michael Ossipoff 
wrote:

>  BTW, I like sundials that tell the ecliptic-months, Aries thru Pisces.
>
> …for which one would need the Solar declinations for the beginning of each
> ecliptic-month, & preferably also for some fractions of each
> ecliptic-month, such as 1/3 & 2/3.
>
> On Fri, Oct 14, 2022 at 10:16 PM Michael Ossipoff 
> wrote:
>
>>
>>
>> -- Forwarded message -
>> From: Michael Ossipoff 
>> Date: Fri, Oct 14, 2022 at 10:16 PM
>> Subject: Re: How to turn ecliptic longitude into solar declination?
>> To: Steve Lelievre 
>>
>>
>>
>>
>> Or you  could just use the ecliptic longitude, reckoned as usual from the
>> Vernal Equinox…multiply its sine by the sine of the obliquely & take the
>> inverse sine of the result.
>>
>> I’d suggested that other way because there are some spherical
>> trigonometry formulas that require an argument between 0 & 90 degrees.
>>
>> …but that isn’t one of them.
>>
>>>
>>>
>>> On Fri, Oct 14, 2022 at 6:49 PM Michael Ossipoff 
>>> wrote:
>>>
>>>> Multiply the sine of ecliptic longitude (reckoned forward or backwards
>>>> from the nearest equinox) by the sine of 23.438 or whatever the current
>>>> obliquity’s exact value is).
>>>>
>>>> Take the inverse sine of the result.
>>>>
>>>> On Fri, Oct 14, 2022 at 4:57 PM Steve Lelievre <
>>>> steve.lelievre.can...@gmail.com> wrote:
>>>>
>>>>>
>>> Of course you’ll know when the declination is negative or positive, so
>>> mark it accordingly.
>>>
>>>
>>>
>>> Hi,
>>>>>
>>>>> For a little project I did today, I needed the day's solar declination
>>>>> for the start, one third gone, and two-thirds gone, of each zodiacal
>>>>> month (i.e. approximately the 1st, 11th and 21st days of the zodiacal
>>>>> months).
>>>>>
>>>>> I treated each of the required dates as a multiple of 10 degrees of
>>>>> ecliptic longitude, took the sine and multiplied it by 23.44 (for
>>>>> solstitial solar declination). At first glance, the calculation seems
>>>>> to
>>>>> have produced results that are adequate for my purposes, but I've got
>>>>> a
>>>>> suspicion that it's not quite right (because Earth's orbit is an
>>>>> ellipse, velocity varies, etc.)
>>>>>
>>>>> My questions: How good or bad was my approximation? Is there a better
>>>>> approximation/empirical formula, short of doing a complex calculation?
>>>>>
>>>>> Cheers,
>>>>>
>>>>> Steve
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> ---
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>>>>>
>>>>>
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