Re: Advice sought re:transparent sundial design

[Thibaud Taudin Chabot]

You can create a 'projected' sundial by placing 
the sundial pattern inside the opening. The 
shadow of this pattern will move over the reading point on the floor.
See Nass compendium vol 1 nr 3 page 6. I designed 
this type as a vandal proof dial, it is 
transparant "projection type". No parts that can be broken or removed.
The pattern can be on a perspex pane placed 
inside the parapet but you can also keep the 
parapet open and create the pattern by placing 
wires in the parapet to get the reuired pattern.

Thibaud


At 17:34 21-4-2020, Alon Gan wrote:

Dear dialist,

I have a 0.8x3.8 meter opening in a wall on the 
roof (technically, a parapet, I believe) which 
is facing west (5.6 degrees north of West, 
actually). After much consideration I came to 
the conclusion that I would like to have a faux 
stained glass sundial (i.e., printed on a large 
pane of glass) with gnomons on both sides of the 
glass, one for showing morning times and the other for the afternoon.
(see attached image showing a very rough example 
of what I have in mind). If it helps, I live at 
32°22’40â″N 
34°52’8 ³E.Â


Please see if you can help me with any one of the following questions:
1. Do you know of any example of such a dial I can study?
2. Due to the elongated dimensions, I think I 
can include additional dials (e.g., direction of 
the sun, etc.) - do you have any ideas?Â
3. I'm trying to decide between a regular 
"linear" gnomon to a spherical gnomon/nodus on a 
perpendicular rod rising from the cornice below. Any ideas?
4. Any interesting ways of including EoT data 
(e.g., connecting to date using a nodus?)


And also for a technical question -
5. I use Shadows for the design (unless you have 
other recommendations), I want to convert the 
data to visio or any other free CAD editor and 
after I design all the dials together, convert 
it again to photoshop, for an artist to design 
it graphically. Any thoughts on easy ways to do all of those conversions?


Thanks a lot

(You can also contact me privately at alongan(at)gmail.com

Best, Alon Gan

.
example alon sundial.jpg


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Content-ID: 
X-Attachment-Id: ii_k9a1lr3q0


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Re: maximum size of e-mails to sundial list including attachments

[Thibaud Taudin Chabot]

I would welcome a limit of 1MB.
Thibaud

At 22:50 30-9-2019, Daniel Roth wrote:

Dear members of the sundial mailing list!

As I'm seeing more often that e-mails to the sundial mailing list 
are being blocked because of the size of the attachments I would 
like to remind you that there is a limitation of the accepted size 
of messages to the list, which is 290 kB. We agreed on this size 
several years ago, because bandwidth for many of us was low. 
Nowadays this might not be the case anymore for most of us. Attached 
images to an e-mail might be very helpful and informative. However, 
resizing down the images is sometimes difficult with the mentioned limitation.


Please let me know your thoughts about this, whether we shall 
increase the limit now to e.g. 1 MB.


Thank you all for your valuable contributions to this list, which I 
founded back in 1996!


Best regards

Daniel Roth, sundial mailing list

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Re: How good is a cell phone compass

[Thibaud Taudin Chabot]

I use the app "GPS status" which has a calibration unction for the 
compass. After calibration the compass is pretty good


At 21:58 11-9-2018, Steve Lelievre wrote:

On 2018-09-11 12:49 PM, Richard Langley wrote:

There must be some specs somewhere on the Web.


Unfortunately, the only spec I've found just says the phone has an 
electronic compass - no accuracy stated.


Chat on discussion lists seems to a bit scathing but most relates to 
older phones.


Steve



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Re: DMARC Wrapping.

[Thibaud Taudin Chabot]

Daniel,
I think you are right. I did a quick check and 
see that a "DMARC message" is sent from a 
different email address then what is on the list.

A check by the persons concerned would be helpfull for all subscribers.
Thibaud

At 11:45 11-9-2018, Daniel Roth wrote:

Dear All,

As the list administrator I'm writing to you 
that the DMARC topic is annoying a lot of 
mailing list users. Some explanations are given 
here: https://wiki.list.org/DEV/DMARC


This sundial mailing list is currently hosted by 
a Mailman version 2.1.29 installation (I have no influence on this).


Yet, I could not dive into the topic and the 
implications of changing settings in the Mailman 
software. Before changing any setting, you as a 
member of the list would have to check that you 
are sending to the sundial mailing list from the 
address with which you have subscribed to the 
list. You can check this here: 
https://lists.uni-koeln.de/mailman/listinfo/sundial


Best regards
Daniel Roth, sundial mailing list


Roger schrieb am 11.09.2018 05:31:

>
> We are all frustrated by the overhead on 
these DMARC wrapped messages. The emails 
generally contain valuable information like 
Kevin Karney’s link. Why are these massages 
“not DMARC compliant?” Generally because 
the sender has changed their email address. 
Perhaps they contain hypertext. Perhaps it is 
the nanny state insisting on things that 
restrict freedom  “for your 
protection”.  My advice is to seek the 
content and ignore the overhead. Check the 
properties and source for your typical emails. 
They also have a lot of similar but hidden 
overhead. I enjoy the benefits but still 
“rage, rage against the fading of the 
light”*, the enlightenment we all receive from these postings.

>
>
>
> Thanks Kevin for sharing such an excellent 
study on the equation of time. 
https://Equation-of-Time.info  with hypertext removed

>
>
>
> Regards,
>
> Roger Bailey
>
> Walking Shadow Designs
>
>
>
> *“Do Not Go Gently..” Dylan Thomas
>
>
>
>
>


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Re: ...

[Thibaud Taudin Chabot]

Why do some messages have such an enormous amount 
of junk text before the actually message?

Can this be skipped in some way?
Thibaud

At 15:58 9-9-2018, John Goodman 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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Re: Solving my Sundial-Quiz from this Week

[Thibaud Taudin Chabot]

Very easy to find the actual location of this 
sundial, check the details of the picture file:

[]

(Breedtegraad=Latitude, Lengtegraad=Longitude, 13.73075N 100.54244E)

At 13:26 26-8-2018, Kurt Niel wrote:

1) The beautiful dial is within the Lumphini 
Park, centre of Bangkok, and is the “Swiss 
Tribute to H.M. the King's Sixth Cycle Birthday“ erected 20 years ago.

2) In the meantime the sundial has been twisted accordingly.

Kurt

Am 24.08.2018 8:04 Vorm. schrieb "Kurt Niel" 
<kepler...@gmail.com>:

...

P.S. Little quiz:
1) Anybody knows this sundial here -where am I?
2) Whats wrong with the dial (image taken at 4 pm)?

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Re: The utility of sundials today.

[Thibaud Taudin Chabot]

A sundial is a timing device entirely driven by solar power and has 
an automatic and precise reset after powerfailure... ;-)


At 20:26 14-1-2018, Willy Leenders wrote:

When I talk about sundials, I get the question: "What utility can 
sundials have today?"
In order to be able to give an answer as diverse as possible, I 
would like to receive your answer to this question



Willy Leenders
Hasselt in Flanders (Belgium)

Visit my website about the sundials in the province of Limburg 
(Flanders) with a section 'worth knowing about sundials' (mostly in 
Dutch): http://www.wijzerweb.be








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Re: Great Circle Studios webpage gone?

[Thibaud Taudin Chabot]

I google with your text "Great Circle Studio's solar data calculator" and find:
 http://www.redrok.com/solcalcjava1.htm
I guess that is the page you want.
Thibaud

At 20:43 12-10-2017, Steve Lelievre wrote:
I've tried to access the Great Circle Studio's solar data calculator 
a couple of time recently, but the website seems to be unavailable. 
Can anyone tell me if it's permanently gone, as opposed to suffering 
a temporary problem?


I'll miss it if it is gone... it is/was a great site for getting 
solar position and EoT data.


Steve
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Re: Dial face colouration

[Thibaud Taudin Chabot]

My experience is use a mat finish sand color. It 
also matches with nearly every colorscheme.


At 03:25 26-2-2017, Michael Ossipoff wrote:
It seems to me that Steve's question has been 
mostly disregarded rather than answered.


Not having experience with translucent 
dial-faces, I didn't know about their lack of 
accuracy, and I certainly can't disagree with 
what two people have said about that.


It means that the advantage of a translucent 
dial, for omnidirectional reading, comes with a 
disadvantage of less precise accuracy.


But of course a high-mounted dial intended for 
relatively distant reading might not be as 
concerned with fine accuracy as with 
omnidirectional viewing. And so translucent 
dials for all-directions viewing certainly aren't ruled-out.


Steve's main question was about the choice of 
dial-face hue, saturation and brilliance, for 
easy and safe dial-reading. It seems to me that 
Steve's question has been mostly disregarded and 
discounted rather than answered.


I lied.

I said that I can't speak from experience on that matter.

But my experience with a few paper-on-cardboard 
tablet-dials is sufficient to say this:


From my experience, I can say that you 
definitely don't want a white dial-face.


As I said, my first dial had a white dial-face. 
After that, I switched to brown, which was a big improvement in usability.


I suggest brown instead of white.

Someone implied that, the more contrast (between 
light and shadow), the better. Not so, when the 
dial-face is too white to look at in bright sunlight.


As for gray: Gray reflects the visible 
wavelengths in a relatively equal mix, resulting 
in no perceived hue. If some hues are (at least 
relatively) to be avoided, then obviously gray isn't what you want.


At each end of the visible spectrum, there is, 
of course, radiation that isn't visible.

Infrared (IR) and ultraviolet (UV).

 One possible disadvantage of that is that, 
when you don't perceive it or its intensity, 
then of course you could conceivably get a 
dangerous amount (accutely or cumulatively) without any perception of it.


For example, never look at the sun when, due to 
a haze, or due to the sun being low in the sky, 
the sun doesn't look bright. You don't have any 
perception of how ingtense the UV or IR is. It 
could burn your eye without any feeling of 
discomfort. (I don't know which of those is more 
dangerous, but there have been official warnings 
to never look at the sun when it seems less 
bright due to haze or low altitude.)


Aside from that, there's been evidence that, 
when people spend a lot of time outdoors, in 
bright sunny climate, then many years of 
exposure to the bright blue light can cause some 
long-term cumulative damage. So maybe blue isn't the most desirable hue.


Yellow, beings the complement of blue, looks 
yellow because it absorbs blue, removes blue from the light that it reflects.


Also, yellow isn't particularly close to either end of the visible spectrum.

Brown is defined as:

"Any of a group of colors between red and yellow 
in hue, of medium to low brilliance, and of moderate to low saturation."


Then, dark brown would be brown with 
particularly low brilliance--a desirable 
attribute for a sundial-face. Might that be the best color for a dial-face?


Tan is defined as:

"Light yellowish brown."

...suggesting more brilliance than brown (but 
surely a lot less than white), and enough 
saturation to be perceived as yellow, which seems a good thing.


Brown, especially dark brown, or maybe tan, 
sound like acceptable colors for a dial-face.


By the way, beige is defined as:

"A variable color averaging light grayish yellowish brown."Â

Sounds like tan, but with distinct grayness, 
lower saturation, making it probably less desirable.


In my previous post I said that I bought brown 
construction-paper, but didn't use it, and, 
instead, just marked the hour-lines on the 
corrugated cardboard instead of using paper. 
Actually, I probably did use the brown 
construction-paper. It looks better of course, 
and it allowed me to conveniently use a 
carbon-paper template that I'd prepared for drawing the hour-lines.


Maybe the plain cardboard dial-face would have 
easier construction in one way, and less easy 
construction in another way. Maybe I tried one 
all-cardboard dial. It was a long time ago.


Michael Ossipoff





Â









On Fri, Feb 24, 2017 at 1:04 PM, Steve Lelievre 
<steve.lelievre.can...@gmail.com> 
wrote:

Fellow sundiallers,

I’m planning to make my next sundial from 
outdoor grade UV resistant plastic sheeting. 
These come in a range of colours and I want to 
choose one that works well for a sundial. 
Assuming I get the material grit-blasted or 
somehow treated so that it not shiny, and 
leaving aesthetic considerations aside, what 
light-related attributes should I be looking for?


As anyone who has played with paper sundials 
knows, a white surface is hard 

Re: Looking for minutes and seconds correction for whole year for Equation of Time plaque

[Thibaud Taudin Chabot]

Some time ago when I was able to use the 
mainframe computer of my employer I made a list 
of declination and time equation for each day for 
the years 2000-2099 and calculated the mean 
values for each date. I found the list again and 
attach it for who is interested.

Thibaud


Hi everyone,


 I am working on my Equation of Time plaque 
for my aluminum cross sundial.  All the 
instructions and graphics and EQT will be on an 
8 ½” diameter ½” aluminum plate.  I do not want 
to use the standard graph found on many 
sundials but instead a chart for the whole 
year, mins and secs, to add or subtract total 
correction to get watch time.  I do not have 
much room for detailed instructions.



 I looked at difference sources for the 
chart and would like to verify the most 
accurate times to use the four year leap year 
cycle for a church at 40.1526N, 76.6038W.   I 
have looked at the Solar Noon calculator, Sonne 
and Shadows-(cannot input decimal 
degrees?)  Are there other sources or spreadsheet programs?



 I like to convey that sundials are 
accurate.  I envision that a person will wait 
till the shadow is on a line and the person 
will know what time it is suppose to be even 
though this type of sundial may not be design for precision.



 I made a quick drawing.  There will be 
some type of sun image at the top and a logo at 
the bottom for the location.  The chart in the 
center is from another project that I did just 
to see how it would look and if the printing is 
large enough to read.  I would have to change 
the inputs to standard time for the whole 
year.  I have also attached a picture of the sundial.



 I just want to know if I am using the 
right times and would appreciate any comments or suggestions.



Thanks very much


Ken 
Clark 
Elizabethtown, PA



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Mean values declination sun and time equation at 12:00 GMT
calculated over the years 2000 - 2099
==
   Day   - Declination sun    -- time equation ---
DatenrDD:MM:SS.ssDD.ddSSS.ssH:MM:SS.ssH.hh
--
01JAN   1-22:58:00.38   -22.966771   -211.953356   -0:03:31.95   -0.058876
02JAN   2-22:52:40.95   -22.878043   -239.917845   -0:03:59.92   -0.066644
03JAN   3-22:46:54.21   -22.781725   -267.534094   -0:04:27.53   -0.074315
04JAN   4-22:40:40.32   -22.677866   -294.772817   -0:04:54.77   -0.081881
05JAN   5-22:33:59.46   -22.566516   -321.605383   -0:05:21.61   -0.089335
06JAN   6-22:26:51.82   -22.447729   -348.003856   -0:05:48.00   -0.096668
07JAN   7-22:19:17.63   -22.321563   -373.941044   -0:06:13.94   -0.103873
08JAN   8-22:11:17.09   -22.188079   -399.390535   -0:06:39.39   -0.110942
09JAN   9-22:02:50.43   -22.047343   -424.326734   -0:07:04.33   -0.117869
10JAN   10   -21:53:57.92   -21.899421   -448.724903   -0:07:28.72   -0.124646
11JAN   11   -21:44:39.79   -21.744385   -472.561195   -0:07:52.56   -0.131267
12JAN   12   -21:34:56.31   -21.582309   -495.812681   -0:08:15.81   -0.137726
13JAN   13   -21:24:47.77   -21.413269   -518.457388   -0:08:38.46   -0.144016
14JAN   14   -21:14:14.45   -21.237347   -540.474318   -0:09:00.47   -0.150132
15JAN   15   -21:03:16.64   -21.054623   -561.843480   -0:09:21.84   -0.156068
16JAN   16   -20:51:54.66   -20.865184   -582.545908   -0:09:42.55   -0.161818
17JAN   17   -20:40:08.82   -20.669116   -602.563685   -0:10:02.56   -0.167379
18JAN   18   -20:27:59.44   -20.466511   -621.879958   -0:10:21.88   -0.172744
19JAN   19   -20:15:26.85   -20.257459   -640.478956   -0:10:40.48   -0.177911
20JAN   20   -20:02:31.40   -20.042056   -658.346003   -0:10:58.35   -0.182874
21JAN   21   -19:49:13.43   -19.820398   -675.467526   -0:11:15.47   -0.187630
22JAN   22   -19:35:33.30   -19.592582   -691.831067   -0:11:31.83   -0.192175
23JAN   23   -19:21:31.36   -19.358710   -707.425286   -0:11:47.43   -0.196507
24JAN   24   -19:07:07.98   -19.118883   -722.239967   -0:12:02.24   -0.200622
25JAN   25   -18:52:23.54   -18.873204   -736.266017   -0:12:16.27   -0.204518
26JAN   26   -18:37:18.40   -18.621779   -749.495468   -0:12:29.50   -0.208193
27JAN   27   -18:21:52.97   -18.364713   -761.921470   -0:12:41.92   -0.211645
28JAN   28   -18:06:07.61   -18.102114   -773.538288   -0:12:53.54   -0.214872
29JAN   29   -17:50:02.72   -17.834090   -784.341294   -0:13:04.34   -0.217873
30JAN   30   -17:33:38.71   -17.560752   -794.326959   -0:13:14.33   -0.220646
31JAN   31   -17:16:55.95   -17.282209   -803.492836   -0:13:23.49   -0.223192
01FEB   32   -16:59:54.87   -16.998574   -811.837555   

Re: An interesting piece of timekeeping

[Thibaud Taudin Chabot]

That is exactly the reason why I asked why that 
app wasn't created yet (for android)


At 08:22 18-1-2017, Douglas Bateman wrote:

For the iPad...

Regards, Doug

image1.PNG


Sent from my iPad

On Jan 18, 2017, at 5:25 AM, 
rodwall1...@gmail.com 
<rodwall1...@gmail.com> wrote:



Hi Jack,

Is this for Android? I couldn't find it.

Roderick Wall.

- Reply message -
From: "Jack Aubert" <j...@chezaubert.net>
To: "'David Patte ₯'" 
<dpa...@relativedata.com>, 
<sundial@uni-koeln.de>

Subject: An interesting piece of timekeeping
Date: Wed, Jan 18, 2017 10:17 AM


The smartphone app has been written.

Look for Chronometer by Emerald Sequoia.  You 
can easily spend hours exploring it.  It 
consists of fifteen different virtual watches, 
each one offering a different set of temporal and astronomical features.




Jack Aubert



From: sundial 
[mailto:sundial-boun...@uni-koeln.de] 
On Behalf Of David Patte ?

Sent: Monday, January 16, 2017 10:11 PM
To: sundial@uni-koeln.de
Subject: Re: An interesting piece of timekeeping



True, but if I can get 125 sponsors of $400 
each I can write you a smartphone app that has 
all the same features, looks similiar, and is 
10 times more accurate - and it will adjust to 
your local timezone and labelling in 10 languages to boot :)




 2017-01-16 21:42, J. Tallman wrote:

It is not a sundial, but interesting nonetheless:

http://www.ablogtowatch.com/vacheron-constantin-les-cabinotiers-celestia-astronomical-grand-complication-3600-watch/

It is quite a feast for the eyes, and the 
mind...and if you have a spare million lying around, it could be yours!




Best,

Jim Tallman
Artisan Industrials

www.artisanindustrials.com 

www.spectrasundial.com 

jtall...@artisanindustrials.com 


513-253-5497






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Re: An interesting piece of timekeeping

[Thibaud Taudin Chabot]

Why didn't you create that app yet? Comming soon? ;-)

At 04:10 17-1-2017, David Patte ₯ wrote:
True, but if I can get 125 sponsors of $400 each 
I can write you a smartphone app that has all 
the same features, looks similiar, and is 10 
times more accurate - and it will adjust to your 
local timezone and labelling in 10 languages to boot :)


 2017-01-16 21:42, J. Tallman wrote:

It is not a sundial, but interesting nonetheless:

http://www.ablogtowatch.com/vacheron-constantin-les-cabinotiers-celestia-astronomical-grand-complication-3600-watch/

It is quite a feast for the eyes, and the 
mind...and if you have a spare million lying around, it could be yours!


Best,

Jim Tallman
Artisan Industrials

www.artisanindustrials.com
www.spectrasundial.com
jtall...@artisanindustrials.com
513-253-5497
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Re: STONE SUNDIAL

[Thibaud Taudin Chabot]

How was it done with the stones of Stonehenge?

At 21:09 1-11-2016, Dennis Cowan wrote:
Does anyone know of a facility in the UK where a piece of stone from 
a sundial can be sent to try to establish where the stone originated from?


Dennis Cowan

Sent from my Mobile
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Re: Terms to describe markings on dials (or other objects)

[Thibaud Taudin Chabot]

Recessed?
__
Th. Taudin Chabot



-- Origineel bericht --
Van: "John Pickard" 
Aan: "Sundial List" 
Verzonden: 28-10-2016 00:12:02
Onderwerp: Terms to describe markings on dials (or other objects)


Good morning,

As part of my research on wire strainers (tools used to tighten wire in 
fences) I am struggling with trying to find some generic terms to 
describe the markings (patent numbers, part numbers and other 
information) on the tools.


My problem is that the markings are either "raised" (embossed) or 
"lowered" (engraved / stamped). The method of marking can be via 
casting, forging, or hand-stamping. What I am looking for is a generic 
term for the "lowered" markings. I have seen the word "debossed" as an 
antonym of "embossed", but it seems to be a neologism created 
specifically for this purpose.


I'm trying to avoid using "cast", "forged" or "stamped" as these terms 
are all about the method of marking, not about the form of the 
markings. And both cast and forged markings can be either raised or 
lowered. This is not just an issue for me and the wire strainers I'm 
working on. Zillions of objects in museums have markings that need to 
be described, but I've been unable to find a suitable term to include 
in the "restricted vocabulary" I am developing for my work.


I'm quite happy to use "raised" as a simple, clear and neutral (i.e. 
independent of the method or marking) term for any embossed markings, 
but I would welcome any suggestions for a similar generic term for 
markings that are below the surface. I've looked at various thesauri 
(pedant!), but so far I haven't found any terms that really works.




Cheers, John

John Pickard
john.pick...@bigpond.com

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Re: No decision on future of leap seconds

[Thibaud Taudin Chabot]

The leap second is to get all clocks in the world synchronized to the 
sundials ... ;-)


At 19:01 23-11-2015, Wolfgang R. Dick wrote:
Content-Transfer-Encoding: base64ITU-R has decided not to decide 
anything now on the future of

leap seconds, but has postponed a decision to 2023 - see below.

By the way, am I right that all sundials would show wrong time
earlier or later if no leap seconds would have introduced?
(I mean at least the precise sundials which correct for the
equation of time and show time with a precision of minutes or even
better.)

A second question: What are the most precise sundials? In Furtwangen
I saw a large sundial with a claim to disply time to a second,
but I could not recognize this precision on the sundial itself.

And a third question: Are there already thoughts how to construct
a precise sundial in a world without leap seconds, when the zero
meridian for time will no longer be coincide with the geographic
zero meridian and will be shifted eastwards with time?

Best regards,
Wolfgang


Coordinated Universal Time (UTC) to retain "leap second"

New reference time scale to be considered by World Radiocommunication
Conference in 2023

Geneva, 19 November 2015 - The ITU World Radiocommunication Conference
(WRC-15), currently in session in Geneva from 2 to 27 November, has
decided that further studies are required on the impact and application
of a future reference time-scale, including the modification of
coordinated universal time (UTC) and suppressing the so-called "leap
second".

Leap seconds are added periodically to adjust to irregularities in the
earth's rotation in relation to Coordinated Universal Time (UTC), the
current reference for measuring time, in order to remain close to mean
solar time (UT1). A leap second was added most recently on 30 June 2015
at 23:59:60 UTC. The proposal to suppress the leap second would have
made continuous reference time-scale available for all modern electronic
navigation and computerized systems to operate while eliminating the
need for specialized ad hoc time systems.

The decision by WRC-15 calls for further studies regarding current and
potential future reference time-scales, including their impact and
applications. A report will be considered by the World
Radiocommunication Conference in 2023. Until then, UTC shall continue to
be applied as described in Recommendation ITU-R TF.460-6
[https://www.itu.int/rec/R-REC-TF.460-6-200202-I/en] and as maintained
by the International Bureau of Weights and Measures (BIPM).

WRC-15 also calls for reinforcing the links between ITU and the
International Bureau of Weights and Measures (BIPM). ITU would continue
to be responsible for the dissemination of time signals via
radiocommunication and BIPM for establishing and maintaining the second
of the International System of Units (SI) and its dissemination through
the reference time scale.

Studies will be coordinated by ITU along with international
organizations such as the International Maritime Organization (IMO), the
International Civil Aviation Organization (ICAO), the General Conference
on Weights and Measures (CGPM), the International Committee for Weights
and Measures (CIPM), the International Bureau of Weights and Measures
(BIPM), the International Earth Rotation and Reference Systems Service
(IERS), the International Union of Geodesy and Geophysics (IUGG), the
International Union of Radio Science (URSI), the International
Organization for Standardization (ISO), the World Meteorological
Organization (WMO), and the International Astronomical Union (IAU).

"Modern society is increasingly dependent on accurate timekeeping," said
ITU Secretary-General Houlin Zhao. "ITU is responsible for disseminating
time signals by both wired communications and by different
radiocommunication services, both space and terrestrial, which are
critical for all areas of human activity."

"The worldwide coordination of time signals is critical for the
functioning and reliability of systems that depend on time," said
Francois Rancy, Director of the ITU Radiocommunication Bureau. "ITU will
continue to work with international organizations, industry and user
groups towards providing coherent advice on current and potential future
reference time-scales."

Source: ITU Press Release,
http://www.itu.int/net/pressoffice/press_releases/2015/53.aspx
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Re: Construction of a Hemispherium

[Thibaud Taudin Chabot]

I think a link for downloading would be handy as more people might be 
interested in this unique documentation.


Thibaud Taudin Chabot
tcha...@dds.nl


__
Sent from eM Client | www.emclient.com



-- Origineel bericht --
Van: "David Brown" <da...@davidbrownsundials.com>
Aan: "Roger Bailey" <rtbai...@telus.net>
CC: "<sundial@uni-koeln.de>" <sundial@uni-koeln.de>
Verzonden: 14-9-2015 10:01:24
Onderwerp: Re: Construction of a Hemispherium


May I have a copy too, please?
David Brown
Somerton
Somerset
UK

Sent from my iPad

On 14 Sep 2015, at 01:32, Roger Bailey <rtbai...@telus.net> wrote:

I have a copy of the webpage and files in a folder. I will send will 
send these files to you individually.


Regards, Roger bailey

From:Dan-George Uza
Sent: Sunday, September 13, 2015 10:57 AM
To:sundial@uni-koeln.de
Subject: Construction of a Hemispherium

Hello!

I am trying to locate a copy of Fer de Vries' website article 
detailing the construction of a hemispherium sundial. The link was 
posted here in 1996 but it is no longer available. Please help if you 
can.


​Dan Uza




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No virus found in this message.
Checked by AVG - www.avg.com
Version: 2015.0.6086 / Virus Database: 4419/10633 - Release Date: 
09/13/15


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Re: A translucent sundial

[Thibaud Taudin Chabot]

Where and how to read time? That picture fails..

At 07:50 27-7-2015, Chi lian Chiu wrote:

​Hi all,

I am very glad to inform you that several 
pictures of the translucent sundial up in the 
sky as I mentioned two years ago are now available at


http://photo.xuite.net/nycl.chiu/6138077/1.jpghttp://photo.xuite.net/nycl.chiu/6138077/1.jpg

http://photo.xuite.net/nycl.chiu/6138077/2.jpg

http://photo.xuite.net/nycl.chiu/6138077/3.jpghttp://photo.xuite.net/nycl.chiu/6138077/3.jpg

http://photo.xuite.net/nycl.chiu/6138077/4.jpg

http://photo.xuite.net/nycl.chiu/6138077/5.jpghttp://photo.xuite.net/nycl.chiu/6138077/5.jpg

Â

The dial is attached to a public art sculpture, “The Gate of Ecology”.

name:Â  The Sundial of Ecology

type:Â  sloped

face plate material: Â 5 mm plus 8 mm double tempered glass

face treatment:Â  sandblasted to be translucent, 
leaving hour-lines transparent


hour numerals:Â  marked on the frame, not on the face plate

gnomon material: Â stainless steel, #304

inclination: Â 10 degrees due west (west end is the lower end)

shape of the plate:Â  oval, 1.8 m by 1.2 m
center height from the ground:Â  5.7 m

location:Â  23.49N, 120.12E

designer:Â  Chi-Liang Chiu (individual) and Mega Design Co.

funding source:Â  Forestry Bureau, Council of 
Agriculture, Taiwan, Rep. of China


built date:Â  Nov. 2013


Have a nice day!


Chi-Liang

24.78N, 120.99E
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RE: A translucent sundial

[Thibaud Taudin Chabot]

So it is actually the same as a window sundial 
but more or less in a horizontal position and 
doesn't project its hourlines on a surface to read time.


At 12:47 28-7-2015, Robert Terwilliger wrote:
If you hold your cursor to the right side of any 
image you will see a carat  that will take 
you to the next photograph - and eventually to  models for the construction.


The time is read by looking up at the translucent ellipse as in this photo:

http://photo.xuite.net/nycl.chiu/6138077/4.jpghttp://photo.xuite.net/nycl.chiu/6138077/4.jpg

Google translate also helps.

Bob


--
From: sundial [mailto:sundial-boun...@uni-koeln.de] On Behalf Of Chi lian Chiu
Sent: Monday, July 27, 2015 1:51 AM
To: Sundial sundiallist
Subject: A translucent sundial

​Hi all,

I am very glad to inform you that several 
pictures of the translucent sundial up in the 
sky as I mentioned two years ago are now available at


http://photo.xuite.net/nycl.chiu/6138077/1.jpghttp://photo.xuite.net/nycl.chiu/6138077/1.jpg

http://photo.xuite.net/nycl.chiu/6138077/2.jpg

http://photo.xuite.net/nycl.chiu/6138077/3.jpghttp://photo.xuite.net/nycl.chiu/6138077/3.jpg

http://photo.xuite.net/nycl.chiu/6138077/4.jpg

http://photo.xuite.net/nycl.chiu/6138077/5.jpghttp://photo.xuite.net/nycl.chiu/6138077/5.jpg



The dial is attached to a public art sculpture, “The Gate of Ecology”.

name:Â  The Sundial of Ecology

type:Â  sloped

face plate material:Â  5 mm plus 8 mm double tempered glass

face treatment:Â  sandblasted to be translucent, 
leaving hour-lines transparent


hour numerals:Â  marked on the frame, not on the face plate

gnomon material:Â  stainless steel, #304

inclination:Â  10 degrees due west (west end is the lower end)

shape of the plate:Â  oval, 1.8 m by 1.2 m
center height from the ground:Â  5.7 m

location:Â  23.49N, 120.12E

designer:Â  Chi-Liang Chiu (individual) and Mega Design Co.

funding source:Â  Forestry Bureau, Council of 
Agriculture, Taiwan, Rep. of China


built date:Â  Nov. 2013



Have a nice day!



Chi-Liang

24.78N, 120.99E
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Re: App for iPad

[Thibaud Taudin Chabot]

Not direct for sundialing but you might be interested in Sun 
Surveyor. There is free light version and a paid pro version.

Thibaud

At 17:36 13-1-2015, Larry McDavid wrote:
Tony's report of this phone app for the iPad has made me wonder if 
any of us uses an Android app for a smart cell phone that provides 
a similar orrery function.


I just got a new Galaxy S5 smart cell phone with a large oled 
display. Can anyone recommend an Adroid app helpful with sundialing?


Larry
NASS

On 1/12/2015 2:14 AM, Tony Moss wrote:

Hi all,
  While restoring lost material on my iPad I searched for an
Orrery app. and discovered   Phaeton .  It is a free application so I
almost didn't bother to download it.  What a mistake that would have been!

If you know about it already then no harm done but, if not, you have an
astronomical treat in store.

...
--
Best wishes,

Larry McDavid W6FUB
Anaheim, California  (SE of Los Angeles, near Disneyland)
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Re: 3D printers

[Thibaud Taudin Chabot]

For a affordable and reliable 3d printer with a high accuracy have a look at:
http://www.mamba3d.com/

Thibaud

At 02:11 5-12-2014, John Pickard wrote:

Good morning,

There was some discussion on the list a few months ago about 3D printers.

One of the leading electronics stores in Australia is now selling 
DIY kits for a small 3D printer (Velleman K8200) for $AUD1300. It's 
a desk-top unit that purely by chance I saw in operation at the 
local library a day or so ago.


http://www.jaycar.com.au/productView.asp?ID=TL4020

More info on the kit: www.k8200.eu

The max dimensions of printed objects is 200 x 200 x 200 mm, which 
would be too small for most outdoor dials, but could be ideal for 
prototyping portable dials (e.g. armillary spheres, ring dials, 
etc.) The printed resolution is: X and Y (wall thickness): 0.5 mm; 
Z: (layer thickness) 0.20 - 0.25 mm. Still not comparable to 
engraving, but an obvious harbinger of things to come. If we think 
about how digital cameras and smart phones now have amazing 
resolution, then most likely the resolution of these 3D printers 
will be much better in a couple of years.


Software is Repetier: www.repetier.com

I have no idea how you enter specifications for an object. I found 
no mention of CAD in my quick reading of material on the Repetier, 
so I guess that they have some other way of doing it.


I have no doubt that similar printers are offered in most countries, 
and one would be a Christmas present!



Cheers, John

John Pickard
john.pick...@bigpond.com

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Re: Deltacad

[Thibaud Taudin Chabot]

[Options], Options, Default directory

At 04:23 15-11-2014, Donald Christensen wrote:

I'm running windows 7

Can I set deltacad to remember a certain 
directory? Or will it simply remember the last one?



Cheers
Donald Christensen
0423 102 090Â Â
http://www.sundialsforlearning.com/www.sundialsforlearning.com

This e-mail is privileged and confidential. If 
you are not the intended recipient please delete 
the message and notify the sender. Un-authorized 
use of this email is subject to penalty of law.

So there!



On Sat, Nov 15, 2014 at 1:57 PM, 
illustratingshadows 
mailto:illustratingshad...@yahoo.comillustratingshad...@yahoo.com wrote:
what operating system and release level? 
deltacad and windows 8.1 remembers the last 
macro folder, but not in windows 8 at least that is what I experienced.


simonÂ


Sent via the Samsung Galaxy Alpha™, an AT;T 4G LTE smartphone


 Original message 
From: Donald Christensen 
mailto:dchristensen...@gmail.comdchristensen...@gmail.com

Date:11/14/2014 19:02 (GMT-07:00)
To: Sundial mailing list mailto:sundial@uni-koeln.desundial@uni-koeln.de
Subject: Deltacad

I have just installed Deltacad and am learning 
how to use it. One question that I have is:


How do I change the default directory? I want 
Deltacad to always look in and save to d:\d deltacad





Cheers
Donald Christensen
0423 102 090Â Â
http://www.sundialsforlearning.com/www.sundialsforlearning.com

This e-mail is privileged and confidential. If 
you are not the intended recipient please delete 
the message and notify the sender. Un-authorized 
use of this email is subject to penalty of law.

So there!



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Re: Map required

[Thibaud Taudin Chabot]

is http://www.mapmaker.com/v3/index.htm  a possible solution for you?
Thibaud

At 20:14 16-8-2014, Tony Moss wrote:

Hi all,
 For a sundialling purpose I need a map of the British 
Isles in Mercator's Projection.  All I have found so far is a 
webpage purporting to offer a Mercator print but its latitude lines 
are curved and the longitude lines converge to the north.  My old 
schoolroom World Map has the UK too small to be useful.  Something 
around A4 size would be ideal.  Suggestions welcome.


Thanks in anticipation,

Tony Moss
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Re: Sun tracks

[Thibaud Taudin Chabot]

Do I see a retrograde? (Same azimut, different moments). Where is 
this picture made?

Thibaud

At 21:33 4-5-2014, Barry Wainwright wrote:
The BBC has a series of pictures taken by pinhole camera at 
http://www.bbc.co.uk/news/in-pictures-27221895


Image 7 is described thus:
John Rigg: This is a six-month exposure using a pinhole camera made 
from an empty soup tin and photographic paper, not film. The 
resulting image is then scanned and reversed. The trails mark the 
path of the sun across the sky as the seasons change. Days with 
broken cloud show as a dotted line.


--
Barry

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Re: The GPS zero meridian club

[Thibaud Taudin Chabot]

There is an android app called GPS averaging that can average many 
readings in order to get a more realistic value of the position.

Thibaud

At 10:44 1-5-2014, Frank Evans wrote:

Greetings, fellow dialists,
Ian Maddocks asks what dials are on whole number lat/long lines.
During the BSS tour of Austria in 2002 we visited a pillar dial 
labelled Nieder osterreich which claimed to be exactly at 48 deg 
N, 15 deg. E.  It is recorded in   Austria 2002; a sundial safari. 
Bulletin of the British Sundial Society, 14, 3, 104-109, 2002 with 
the following: But following the Royal Society's motto Nulius in 
verba (don't believe a word of it) our party produced several 
GPS  machines and the monument' position was found to be a couple 
of thou. out. The suggestion that there were enough of us present 
to shift it to the correct location was reluctantly rejected.

Frank 55N 1W.


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Re: 08:09:10 11/12/13

[Thibaud Taudin Chabot]

Come over to Europe and get a second chance. Here we have 11/12/13 in 
December (and be present at 14:15!)

Thibaud

At 19:18 12-11-2013, Bill Gottesman wrote:
Did anyone catch this auspicious moment, 08:09:10 11/12/13?  I 
missed it, but will go for another try this PM.


-Bill
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Re: sunrise/set/twilight calculators ?

[Thibaud Taudin Chabot]

My pc has UTC+1 + daylightsaving time. UTC+1 is Central European time

At 10:32 5-9-2013, Tony Finch wrote:

Thibaud Taudin Chabot tcha...@dds.nl wrote:

 for my coordinates 52.30N 4.85E sumwait gives the times using the Western
 European time. However on the continent for this longitude the Central
 European time is used.

It just uses your computer's timezone setting - it doesn't have a
geographical database of timezones.

Speaking of time zones and hours of daylight, I have a modified version of
sunwait that prints sunrise time tables, following the scheme I outlined
in RISKS a few years ago. http://catless.ncl.ac.uk/Risks/25.10.html#subj1

Tony.
--
f.anthony.n.finch  d...@dotat.at  http://dotat.at/
Forties, Cromarty: East, veering southeast, 4 or 5, occasionally 6 at first.
Rough, becoming slight or moderate. Showers, rain at first. Moderate or good,
occasionally poor at first.


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Re: sunrise/set/twilight calculators ?

[Thibaud Taudin Chabot]

for my coordinates 52.30N 4.85E sumwait gives the times using the 
Western European time. However on the continent for this longitude 
the Central European time is used.


At 17:49 4-9-2013, Rob Seaman wrote:

And the winners are:

Pyephem turns out to be layered on Elwood Downey's Xephem - can't go 
wrong there!


However, rather than the usual python package management minuet, 
sunwait is an old-school software tool - just compile and run giving 
all the numbers I asked for with one command:


% ./sunwait -p 30.1697S 70.8065W
Using location: 30.169700S, 70.806500W
Date:4 Sep 2013
Local time: 11:31
Day length: 11:39 hours
With civil twilight 12:25 hours
With nautical twilight  13:20 hours
With astronomical twilight  14:16 hours
Length of twilight:  civil   0:22 hours
  nautical   0:50 hours
  astronomical   1:18 hours
Current specified time zone: CLT (-4 from UTC)
Sun transits meridian 1241 CLT
   Sun rises 0653 CLT, sets 1830 CLT
   Civil twilight starts 0629 CLT, ends 1854 CLT
Nautical twilight starts 0601 CLT, ends 1922 CLT
Astronomical twilight starts 0533 CLT, ends 1949 CLT

Interested in the nights not the days so will have to run it for the 
preceding date, too.  Will add moonrise/set/phase some other time :-)


Thanks!

Rob
--

On Sep 4, 2013, at 6:44 AM, Richard B. Langley 
mailto:l...@unb.cal...@unb.ca wrote:



http://rhodesmill.org/pyephem/rise-set.html#naval-observatory-risings-and-settingshttp://rhodesmill.org/pyephem/rise-set.html#naval-observatory-risings-and-settings



On Sep 4, 2013, at 6:45 AM, Tony Finch 
mailto:d...@dotat.atd...@dotat.at wrote:



http://risacher.org/sunwait/http://risacher.org/sunwait/


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Re: Sundial in BBC series

[Thibaud Taudin Chabot]

No it was not an Egyption dial. It was a round horintal dial, 
greenish in colour, I guess bronze.

Now with picture attached

At 22:00 19-8-2013, Willy Leenders wrote:

Thibaud,

I did not see the broadcast but read the English subtitles at this 
address: 
http://tvguide.lastown.com/bbc/preview/precision/the-measure-of-all-things-1-time-and-distance.htmlhttp://tvguide.lastown.com/bbc/preview/precision/the-measure-of-all-things-1-time-and-distance.html 


It is apparently the Egyptian sundial from 1500 BC.
On my website you can see an article about this sundial.
In Dutch: 
http://www.wijzerweb.be/egypte.htmlhttp://www.wijzerweb.be/egypte.html
In English: 
http://www.wijzerweb.be/egypteengels.htmlhttp://www.wijzerweb.be/egypteengels.html


Willy Leenders
Hasselt in Flanders (Belgium)

Visit my website about the sundials in the province of Limburg 
(Flanders) with a section 'worth knowing about sundials' (mostly in 
Dutch): http://www.wijzerweb.behttp://www.wijzerweb.be





Op 19-aug-2013, om 20:49 heeft Thibaud Taudin Chabot het volgende geschreven:

Yesterday (sunday) I saw the first  part of the new BBC serie The 
story of measurement on BBC4.
In it was a horizontal sundial of questionabvle design. The style 
foot was situated on the XII mark and the shadow was crossing many hourlines.
I can't imagine that BBC didn't do any serious research and used a 
fancy sundial and even didn't notice that the shadows weren't 
matching the hourlines.

Or did my TV having troubles? You never know in this digital era.
Thibaud

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Sundial in BBC series

[Thibaud Taudin Chabot]

Yesterday (sunday) I saw the first  part of the new BBC serie The 
story of measurement on BBC4.
In it was a horizontal sundial of questionabvle design. The style 
foot was situated on the XII mark and the shadow was crossing many hourlines.
I can't imagine that BBC didn't do any serious research and used a 
fancy sundial and even didn't notice that the shadows weren't 
matching the hourlines.

Or did my TV having troubles? You never know in this digital era.
Thibaud

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Re: Sundial in BBC series

[Thibaud Taudin Chabot]

No it was not an Egyption dial. It was a round horintal dial, 
greenish in colour, I guess bronze.


At 22:00 19-8-2013, Willy Leenders wrote:

Thibaud,

I did not see the broadcast but read the English subtitles at this 
address: 
http://tvguide.lastown.com/bbc/preview/precision/the-measure-of-all-things-1-time-and-distance.htmlhttp://tvguide.lastown.com/bbc/preview/precision/the-measure-of-all-things-1-time-and-distance.html

It is apparently the Egyptian sundial from 1500 BC.
On my website you can see an article about this sundial.
In Dutch: 
http://www.wijzerweb.be/egypte.htmlhttp://www.wijzerweb.be/egypte.html
In English: 
http://www.wijzerweb.be/egypteengels.htmlhttp://www.wijzerweb.be/egypteengels.html


Willy Leenders
Hasselt in Flanders (Belgium)

Visit my website about the sundials in the province of Limburg 
(Flanders) with a section 'worth knowing about sundials' (mostly in 
Dutch): http://www.wijzerweb.behttp://www.wijzerweb.be





Op 19-aug-2013, om 20:49 heeft Thibaud Taudin Chabot het volgende geschreven:

Yesterday (sunday) I saw the first  part of the new BBC serie The 
story of measurement on BBC4.
In it was a horizontal sundial of questionabvle design. The style 
foot was situated on the XII mark and the shadow was crossing many hourlines.
I can't imagine that BBC didn't do any serious research and used a 
fancy sundial and even didn't notice that the shadows weren't 
matching the hourlines.

Or did my TV having troubles? You never know in this digital era.
Thibaud

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Re: Visibly Moving Gnomon Shadows

[Thibaud Taudin Chabot]

Seeing a movement of the shadow is also dependent 
on the surface on which you see the shadow. If 
this surface is very even colored/structured it 
will be more difficult to see a movement then 
when the surface has such a structure (like fine 
grain) that it is easy easier to see the movement..

Thibaud

At 10:40 7-8-2013, JOHN DAVIS wrote:

Hi Kevin (and Peter R et al),

I saw your SML post and will watch with interest what responses it gets.

One point, though: the value of 1.27 mm/sec as 
the lower limit of perception of movement is 
impossibly precise! I suggest that you would get 
+/-50% variation between different observers. 
Also, it will depend heavily on the situation: 
watching a laser spot on a piece of graph paper 
will give a value orders of magnitude different 
to following a distant aircraft on a clear blue 
sky.  What really matters is the rate of angular 
change and a stationary reference point.


Regards,

John
--

Dr J Davis
Flowton Dials


From: Kevin Nute kn...@uoregon.edu
To: sundial@uni-koeln.de; Peter Ransom 
pran...@btinternet.com; JOHN DAVIS john.davi...@btopenworld.com

Sent: Tuesday, 6 August 2013, 21:38
Subject: Visibly Moving Gnomon Shadows


The movement of the gnomon shadow at the famous 
Samrat Yantra equitorial sundial in Jaipur is 
reputed to be clearly visible to someone 
standing near the projection surface. I've read 
it moves as fast as 1 mm/s, though obviously not 
all the time.  At a given latitude, say 40º N, 
can anyone suggest a simple formula for 
estimating how far a projection surface would 
need to be from a vertical or horizontal gnomon 
for the shadow to move at 1.27 mm/s (the 
practical lower threshold of perceptible 
movement) I wonder?   Or in other words, what's 
the smallest sundial you could build to see 
real-time movement of the gnomon shadow with the naked eye?



Kevin Nute
Professor of Architecture
University of Oregon
School of Architecture and Allied Arts
Eugene, OR 97403
USA
mailto:kn...@uoregon.edukn...@uoregon.edu


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--
Th. Taudin Chabot, . tcha...@dds.nl



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Re: Unicode characters for degrees, minutes, seconds above the decimal point.

[Thibaud Taudin Chabot]

This looks not logic.
The unit symbol comes after the value and not in 
between. If you put the ° above the decimal . 
then what unit is the value after the decimal .?
Everywhere the notation [value] [measuring unit] 
is used, even if the [value] has a fractional part.

But an artist never really looks at rules and makes his own presentation.
Thibaud

At 14:25 6-7-2013, Steve Lelievre wrote:

On 06/07/2013 8:38 AM, Barry Wainwright wrote:
It can be done, but how the characters are 
rendered depends very much on the application used to render them.


There are a block of unicode characters called 
Combining Diacritical Marks which are used to 
modify the preceding character. These 
characters include unicode character U-309A 
(UTF-8 E3 82 9A) which is a Combining 
Katakana-Hirangana Semi-voiced sound mark (but 
it looks very much like the degree symbol 
(U-00B0). When this character is 'typed' after 
a period, you get a character that is almost, but not quite, aligned:


This is the unicode typed in as characters: 127. 42


Perhaps also consider the required symbol 
followed by Combining Dot Below U-0323  ( see 
http://www.fileformat.info/info/unicode/char/323/index.htmhttp://www.fileformat.info/info/unicode/char/323/index.htm 
)



For example in MS Word a ring, prime and double 
prime, each followed by Combining Dot Below give


[]



Steve


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Re: new app Sol Et Umbra for Android

[Thibaud Taudin Chabot]

There are more interesting apps for android/iphone like Sunsurveyor. 
That one can come in very handy for sundial placement and design. 
There is a light ((free) version and a paid version with a lot more features.

Thibaud

At 22:49 9-10-2012, sun.di...@libero.it wrote:

If you own an Android device (smartphone or tablet) you may want to take
advantage of the new app Sol Et Umbra that means Sun and Shadow.
It is available for free from the usual Google app market.

Sol Et Umbra is basically an app that shows sun ephemeris for the actual (or
whichever desired) time and date:
- latitude and longitude
- right ascension and declination
- local azimuth and height
- equation of time
- local or time zone sun time
- local or time zone mean time
- time of rise, set and transit (local noon)
- total number of hours of light

Moreover Sol Et Umbra shows the time using italic, babilonic and 
temporal time

systems.
It also shows the time of Muslims prayers (that are strictly related to the
position of the sun): Fajr, Zuhr, Asr1, Asr2, Maghrib and Isha.

Sol Et Umbra can use the orientation sensors available in the device in order
to compute and show the time lines of a sundial designed on the plane of the
display.
The graph is updated after any movement of the device.

Finally the app can show the lighting conditions of a dial that is drawn on
the device plane by means of an azimut / height graph that shows for 
any day in

the year and for any hour in the day when the dial is lighted.

More information on the program are available from my site: http://digilander.
libero.it/orologi.solari/download/SolEtUmbraENU.html

Ciao.
Gian
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Re: Why are schools, across the world, 'banning' analemmatic sundials ?

[Thibaud Taudin-Chabot]

Did any of the schools ever mention what the danger is of an 
analemmatic sundial?

Thibaud

At 16:19 15-5-2012, Martina Addiscott wrote:


Roughly one year ago, I had mentioned on this 'Mailing List' that
our local Educational Authority would not permit us to install an
interactive 'analemmatic' sundial on our school playground - since
their opinion was that it was simply too dangerous, for children !

It now seems that other countries are 'banning' these, for similar
Health and Safety reasons - which I think is totally ridiculous,
and suggest that the general Sundial community should 'protest' to
the people concerned, as otherwise we are in danger of losing the
opportunity to have these interesting outdoor educational projects.


I know that they are generally 'frowned-upon', by schools here in
Britain - but it appears that Canadian and Australian schools have
also decided, that these 'Human Sundials' cause too much trouble !

See the page at:  www.sunclocks.com/pics/fs-007.htm#reconstituted


If anyone might like to join me in a 'campaign', to stop sundials
being discouraged by schools - then please get in touch with me by
E-mail, or you could also contact me on my mobile: +44 7769561152.

Should anyone have comments on this deplorable situation - then I
would also appreciate your thoughts, direct to the 'Mailing List'.


Sincerely,

Martina Addiscott.


--

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Re: paper sundial

[Thibaud Taudin-Chabot]

Thanks for the link.
I tried to save the location data after having 
been logged in. That didn't work (yet).

Thibaud

At 12:09 15-12-2011, Fabio nonvedolora wrote:

Hi all, news from the clouds.

I’ve a toy for the end of the year.
I don’t think this is the very last end of the 
year, like some Maya supposed, and this is a 
great year, it is better than 2012 :-)  (like 
the same Maya didn’t know) so I hope you have 
fun with this new section of Sundial Atlas.


You can reach ‘paper sundial’, a menu of 
Gnomolab, directly at this address: 
http://www.sundialatlas.eu/atlas.php?gnomolab=3www.sundialatlas.eu/atlas.php?gnomolab=3
You will find 4 models, this number is growing 
and if you have other models to propose, I’ll 
be happy to develop them in Gnomolab.


The models may be setted for any coordinates and 
other features, you will get a pdf as replay.
The 3rd model is designed to be applied to glass 
windows (you may found the declination of the 
windows with Gnomolab). It has a small gnomonic 
hole you can do with a pin or a small nail, 
moreover this model may be customed with a photo 
(or a logo). I uploaded some sample photos but 
anyone may upload other photos (public or for personal use).


Have fun, ciao, Fabio

Fabio Savian
Paderno Dugnano, Milan, Italy
45° 34' 10'' N, 9° 10' 9'' E, GMT+1 (DST +2)

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Re: Falling Tree

[Thibaud Taudin-Chabot]

Why would that falling tree be different from other falling trees 
that are in our hearing environment?

Thibaud

At 16:39 11-8-2011, Bill Gottesman wrote:
I think quantum physicists Neils Bohr and Erwin Schrodinger would 
say there is no sound until it is observed.  But I don't understand 
this stuff all too well.

-Bill

On 8/10/2011 7:26 PM, Donald Christensen wrote:

If a tree falls in the forest where no one can hear it, does it make a sound?

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RE: R: RE: Flow of medieval glass

[Thibaud Taudin-Chabot]

NO. Because something has a color because it 
reflects light of a certain wavelength. If there 
is no light there neither a reflection.

Thibaud

At 17:18 11-8-2011, Peter Tandy wrote:

Content-class: urn:content-classes:message
Content-Type: multipart/alternative;
boundary=_=_NextPart_001_01CC5839.F1B00D4C

and if you take an orange into a deep mine 
where there is no light, is it still orange???




--
From: sundial-boun...@uni-koeln.de 
[mailto:sundial-boun...@uni-koeln.de] On Behalf Of Donald Christensen

Sent: 11 August 2011 00:26
To: Simon [illustratingshadows
Cc: Sundial List
Subject: Re: R: RE: Flow of medieval glass

If a tree falls in the forest where no one can hear it, does it make a sound?
On Thu, Aug 11, 2011 at 3:24 AM, Simon 
[illustratingshadows 
mailto:illustratingshad...@yahoo.comillustratingshad...@yahoo.com wrote:

My two cents worth, having worked with glass for decades.

1. don't confuse an object bending under its own 
weight with the object being fluid.


2. since this news group deals with sunlight, we should remember that light
is both a particle and a wave, and there were heated discussions back in
those days.

Now I have to go and finish a sundial I am making.

Simon Wheaton-Smith
http://www.illustratingshadows.comwww.illustratingshadows.com
Silver City, New Mexico W108.2 N32.75 and
Phoenix, Arizona, W112.1 N33.5

--- On Wed, 8/10/11, 
mailto:sun.di...@libero.itsun.di...@libero.it 
mailto:sun.di...@libero.itsun.di...@libero.it wrote:


From: 
mailto:sun.di...@libero.itsun.di...@libero.it 
mailto:sun.di...@libero.itsun.di...@libero.it

Subject: R: RE: Flow of medieval glass
To: Sundial List mailto:sundial@uni-koeln.desundial@uni-koeln.de
Date: Wednesday, August 10, 2011, 11:05 AM
Accepted that glass atoms can migrate because 
they are not linked together, the following question is : at wich speed?


I found the following in wikipedia in the Glass page:

Writing in the American Journal of Physics, 
physicist Edgar D. Zanotto states ...the 
predicted relaxation time for GeO2 at room 
temperature is 1032 years. Hence, the relaxation 
period (characteristic flow time) of cathedral 
glasses would be even 
longer.http://us.mc1110.mail.yahoo.com/mc/welcome?.gx=1.tm=1312996722.rand=9ju6qipj1sgsd#cite_note-38[39] 
(1032 years is many times longer than the 
estimated age of the Universe.) If medieval 
glass has flowed perceptibly, then ancient Roman 
and Egyptian objects should have flowed 
proportionately more ­ but this is not observed. 
Similarly, prehistoric obsidian blades should 
have lost their edge; this is not observed 
either (although obsidian may have a different 
viscosity from window 
glass).http://us.mc1110.mail.yahoo.com/mc/welcome?.gx=1.tm=1312996722.rand=9ju6qipj1sgsd#cite_note-Gibbs-30[31] 
If glass flows at a rate that allows changes to 
be seen with the naked eye after centuries, then 
the effect should be noticeable in antique 
telescopes. Any slight deformation in the 
antique telescopic lenses would lead to a 
dramatic decrease in optical performance, a 
phenomenon that is not 
observed.http://us.mc1110.mail.yahoo.com/mc/welcome?.gx=1.tm=1312996722.rand=9ju6qipj1sgsd#cite_note-Gibbs-30[31] 
There are many examples of centuries-old glass 
shelving which has not bent, even though it is 
under much higher stress from gravitational loads than vertical window glass.


I still believe that glass cannot flow, but if 
it can it is a so slow motion that we cannot appreciate it even in centuries.


Ciao.
Gian

Messaggio originale
Da: mailto:p.ta...@nhm.ac.ukp.ta...@nhm.ac.uk
Data: 10/08/2011 17.45
A: John 
Carmichaelmailto:jlcarmich...@comcast.netjlcarmich...@comcast.net, 
Kevin Karneyke...@karney.com, John 
Pickardmailto:john.pick...@bigpond.comjohn.pick...@bigpond.com

Cc: Sundial Listmailto:sundial@uni-koeln.desundial@uni-koeln.de
Ogg: RE: Flow of medieval glass
a:link {mso-style-priority:99;} 
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15 5 2 2 2 4 3 2 4;} @font-face 
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text-decoration:none none;} @page Section1 
{size:612.0pt 792.0pt; margin:72.0pt 72.0pt 
72.0pt 72.0pt;} div.Section1 {page:Section1;} - 
a:link 

RE: mock stained glass sundial

[Thibaud Taudin-Chabot]

When you have the lines on the glasssurface 
closed to the style/reading point there is 
refraction error. So style and lines on the 
outside or lines and readingpoint (as used in 
dial#50) on the inside will give no trouble at all.

Thibaud

At 18:14 3-8-2011, karon wrote:

Content-Type: multipart/alternative;
boundary==_NextPart_000_13BA_01CC51D6.E9631DE0
Content-language: en-us

Especially with the double paned windows, they 
are very thin panes of glass and very close 
together. I was thinking about that but, it is 
only an issue if you are worried about super 
precise time keeping. For a 
housekeeper/jeweler/wishful thinking artist it 
does not need to be that precise.


Karon Adams
Accredited Jewelry Professional (GIA)
You can send a free Rosary to a soldier!
www.facebook.com/MilitaryRosary
www.YellowRibbonRosaries.com

From: John Carmichael [mailto:jlcarmich...@comcast.net]
Sent: Wednesday, August 03, 2011 11:37 AM
To: 'Mike Shaw'; ka...@karonadams.com; sundial@uni-koeln.de
Subject: RE: mock stained glass sundial

It’s insignificant.



From: Mike Shaw [mailto:jmikes...@ntlworld.com]
Sent: Wednesday, August 03, 2011 8:29 AM
To: ka...@karonadams.com; 'John Carmichael'; sundial@uni-koeln.de
Subject: Re: mock stained glass sundial

If you are going to allow your shadow to pass 
through two panes of glass, will refraction start to become important?


Mike Shaw
53º 22'N 03º02'W
www.wiz.to/sundials
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Re: Sundial Beer Glass

[Thibaud Taudin-Chabot]

They are for sale, look at 
http://www.shop.analemma.nl/E_home.html and look 
under gifts. One of the items is the (beer)glass.

Thibaud

At 14:21 4-7-2011, Tony Moss wrote:

On 04/07/2011 12:42, Jackie Jones wrote:


Hi All,

I thought you might like to see my latest 
sundial, designed with a friend who runs a 
local beer festival in Brighton.  It is at 
http://www.sundialglass.wordpress.comwww.sundialglass.wordpress.com 
It is made to work at 51° north and I will be 
writing about creating it and the problems 
involved in the December Bulletin of the British Sundial Society.


Best wishes,

Jackie



Jackie Jones

50° 50’ 09” N.0° 07’ 40” W.

http://www.silversundials.co.ukwww.silversundials.co.uk

www.sundialglass.wordpress.com





---
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What a wonderful idea!  I predict a significant market success.

Well done!

Tony Moss
---
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---
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RE: OBASIC on a 64 bit Windows 7 PC?

[Thibaud Taudin-Chabot]

Mac,
QB64 is also available for the mac and linux! (www.qb64.net)
Thibaud

At 19:13 15-4-2011, Mac Oglesby wrote:


Hello Friends,

My sincere thanks to those of you who responded to my plea for help 
in attempting to use QBASIC with a 64-bit Windows 7 (Home Premium) computer.


Not sure which road I'll take, but I have decided to keep the new 
computer and worry about QBASIC when I return from a medical 
vacation over the next few weeks.


I've been using a couple of Commodore PET computers at school with 
some 12 year-olds, and I have a long relationship with Macintosh 
stuff. But each time I think I'm beginning to catch on to the PC 
world they change the rules.


Thanks again,

Mac

---
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---
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Re: solar tracking sundial

[Thibaud Taudin-Chabot]

Something like this:
http://nl.wikipedia.org/wiki/Bestand:20100714-012_Amersfoort_-_Zonnewijzer.jpg
Thibaud

At 21:50 16-3-2011, Brent wrote:

Hello;

I have an idea to build a mechanical sundial.

It would have a moving gnomon that would track the sun.

If the gnomon was a hollow pipe, a spot of light would
shine out of the bottom that could be used to indicate a
time and date.

With all of the photo voltaic systems available now the
hardware is fairly easy to find.

I'm thinking I could use a simple dual axis photo sensor
tracking device such as this:

http://cgi.ebay.com/Complete-Solar-Tracker-Sun-Tracker-Kit-/400187219850

Has anyone seen a sun dial like my idea before?

I Googled solar tracker and they also talk about a
chronological tracker. That rotates one axis at the speed
of the earth but in the opposite direction. That would make
a fun sundial as well.

Modern technology offers lots of new possibilities for
sundials. Is anyone trying new designs?

thanks;
brent

---
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---
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Re: Schmoyer Design

[Thibaud Taudin-Chabot]

Very original way of positioning the style. That style has a certain width 
and normally you would see that same width on the hourscale around noon. 
But here it isn't. Schmoyer was not new to sundials, so he must have done 
this on purpose. So what is hidden there?

Thibaud Chabot

At 17:11 20-01-2004, you wrote:

 I have updated the web page to show this:
www.precisionsundials.com/sundial_list.htm
-Bill


-
Thibaud Taudin-Chabot
52° 18' 19.85 North, 04° 51' 09.45 East, alt. -4.50 m
home email: [EMAIL PROTECTED]


-

Re: Schmoyer Design

[Thibaud Taudin-Chabot]

but the large rectangular part at the end is used to create the shadow for 
reading the time and the width of that part is much more than thickness of 
the style. I would have expected a blank area on the time scale of the same 
width as the rectangle.

Thibaud Chabot

At 15:33 21-01-2004, you wrote:

As far as I can tell, there is a noon gap in the dial commensurate with the
gnomon thickness.
-Bill

In a message dated 1/21/2004 4:42:56 AM Eastern Standard Time, [EMAIL PROTECTED]
writes:

 She is a beauty isn't she?
  Very original way of positioning the style. That style has a certain 
width

  and normally you would see that same width on the hourscale around noon.
  But here it isn't. Schmoyer was not new to sundials, so he must have done
  this on purpose. So what is hidden there?
  Thibaud Chabot

-


-
Thibaud Taudin-Chabot
52° 18' 19.85 North, 04° 51' 09.45 East, alt. -4.50 m
home email: [EMAIL PROTECTED]


-

Re: A 'gnomon-less' sundial for locations near the Equator ?

[Thibaud Taudin-Chabot]

airport. The building was L-shaped, one leg a bit higher than the other. A 
wire across the inner angle from one leg to the other leg was possible and 
because the height difference was the angle 1.5°. The hour lines were on 
the parking lot below. The shadow was visible on the parking lot. The 
management liked the design but didn't use it as far as I know.

Thibaud Chabot

At 19:54 18-01-2004, you wrote:


Can any of our Mailing-List experts suggest some horizontal sundial design
suitable for locations almost on the Equator, (actually 2 Degrees North) ?

We have been contacted by a school in Singapore, who would like to install
a large playground sundial - BUT ideally having nothing above ground-level
to cause any 'accidents', or increase the cost/complexity of their layout.
They want to avoid a 'gnomon' obstructing vehicles in the playground area.

MODERN SUNCLOCKS - 'Human Sundials', using YOUR OWN SHADOW to tell time.

Looking for a useful, decorative, yet UNIQUE feature ? - you've found it !
For further details and photographs, see our Website at: www.sunclocks.com

Mail Address: 1 Love Street, Kilwinning, Ayrshire, Scotland, KA13 7LQ, UK.
Tel  Fax (UK): 01294 552250.   International Tel  Fax: + 44 1294 552250.
E-mails to: [EMAIL PROTECTED]   OR   [EMAIL PROTECTED]
-


-
Thibaud Taudin-Chabot
52° 18' 19.85 North, 04° 51' 09.45 East, alt. -4.50 m
home email: [EMAIL PROTECTED]


-

RE: Right Ascension

[Thibaud Taudin-Chabot]

I kept on digging in the books, and found in an old book of Jean Meeus (3rd 
edition, Oct 80):


H=local hour angle, measured westward from the south,
S=the local sidereal time,
S0=siderial time at Greenwhich,
L=the observers longitude (+=West, -=East)
ra=right ascension.
then it is simple:
H=S-ra or H=S0-L-ra

And I love simple formulas.

Thibaud


At 03:00 16-01-2004, you wrote:

Hello Brad, Thibaud and all,

Like Thibaud, I come from the navigation school of astronomy and am more
familiar with SHA than RA. As shown in his equation, subtract from 360 and
change from degrees to time (15 degrees/hour) and they are equivalent.

You need to find the SHA Aries or GMST as a starting point. For a convenient
algorithm, go to the Sky and Telescope website Sky and Telescope
http://skyandtelescope.com/resources/software/article_326_1.asp to find on
page 4 the file  GMST.BAS.  You can run this with a BASIC editor or change
the file name from GMST.BAS to GMST.TXT and open it in a word processor to
look at the source code and extract the algorithm. I noticed it starts with
Julian Date so you will have to calculate that as well. Try the CALCJD.BAS
also available on this site. I am pleased to see that Stuart Goldman and
Roger Sinnott still keep this source active. As an hacker from the old days,
before the term hacker was corrupted, I appreciated the availability of
the source code. We can all benefit from this open code philosophy.

Thanks,

Roger Bailey
Walking Shadow Designs
N 48.6  W 123.4


-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Thibaud
Taudin-Chabot
Sent: January 15, 2004 2:40 PM
To: sundial@rrz.uni-koeln.de
Subject: Re: Right Ascension


At 20:37 14-01-2004, you wrote:
Somewhat off topic, but how do you translate (a) the right ascension of a
star and (b) the current date and time into (c) the apparent longitude of
the star?

I took my old nautical astronomy book and found:

1. SHA(star) = 360 - right ascencion (SHA=siderial hour angle)
2. LHA(star) = GHA(aries) + SHA(star) + East longitude or
 LHA(star) = GHA(aries) + SHA(star) - West longitude(LHA=local hour
angle, GHA=Greenwich hour angle)
The GHA(aries) can be fouynd in the nautical almanac

Thibaud

-
Thibaud Taudin-Chabot
52° 18' 19.85 North, 04° 51' 09.45 East, alt. -4.50 m
home email: [EMAIL PROTECTED]


-

-


-
Thibaud Taudin-Chabot
52° 18' 19.85 North, 04° 51' 09.45 East, alt. -4.50 m
home email: [EMAIL PROTECTED]


-

Re: Sundial inside a room, but room is inside a canyon!

[Thibaud Taudin-Chabot]

I would suggest: create the sundial on your neighbors waal only for the 
hours your south facing wall is not sun lit. For the other hours you can 
make your sundial on your own wall.

Thibaud

At 22:03 04-01-2004, you wrote:

I sketched out a vertical dial, figuring a mirror as the nodus on a pin
gnomon perpendicular to the dial face, using Fer J. de Vries' ZW2000
software. I used my northern California coordinates. It's a *little*
large, for a suburban home. A mirror 10 feet from the plane of the wall
seems to require a dial face on the order of 86 feet wide by 50 feet tall!

If the small attachment comes through, it should explain it...

Dave
37.277N 121.966W

On Sun, 4 Jan 2004, Thibaud Taudin-Chabot wrote:

 Dave, Tom,

 It is not that difficult, mirror the neighbors wall in relation to the
 mirror, so it will be some imaginary wall in Tom's house. The mirror is 
the

 tip of the gnomon, or a little window whatever you like. The south facing
 dial on the mirrored neighbors wall has to be mirrored back: left and 
right

 should switched like top and bottom. And that is simply done by rotating
 the whole design around a horizontal perpendicular axis.

 Thibaud


 At 18:21 04-01-2004, you wrote:
 I love it!
 If Tom can sell his neighbor on the esthetic upgrade to his house, it's a
 great solution.
 
 How does the geometry work out? Would the mirror need to be *very* high,
 say, over 2 stories itself? Closer, or farther than Tom's South wall? I
 guess the design trick would be to calculate a South-facing dial with a
 nodus 10 feet away from the face, and adjust the nodus hieght to fit...
 
 Dave
 37.277N 121.966W
 
 On Sun, 4 Jan 2004, Thibaud Taudin-Chabot wrote:
 
   Tom,
  
   There is an other solution:
   Put a miiror high on your south facing wall which will reflect the 
sun on

   your neighboors North wall.
   Design a sundial for that North Facing wall of your neighboor. He will
   never look at it but you see it all the time.
  
   Thibaud
  
   At 07:36 04-01-2004, you wrote:
   I have a nice, south-facing room.  The trouble is, my neighbor's
  two-story
   house is about 10 feet away, due south.  Consequently,  if I cut an
   aperture in my wall, the sun would find it only mid-summer.  The 
rest of
   the time, my neighbor's roof would block the sun.  Demolishing his 
second

   story is not an option, he says.
   
   Tom Egan
   33.642 N, 117.943 W-
 
 -

 -
 Thibaud Taudin-Chabot
 52° 18' 19.85 North, 04° 51' 09.45 East, alt. -4.50 m
 home email: [EMAIL PROTECTED]


 -



-
Thibaud Taudin-Chabot
52° 18' 19.85 North, 04° 51' 09.45 East, alt. -4.50 m
home email: [EMAIL PROTECTED]


-

Re: Sundial inside a room, but room is inside a canyon!

[Thibaud Taudin-Chabot]

There is an other solution:
Put a miiror high on your south facing wall which will reflect the sun on 
your neighboors North wall.
Design a sundial for that North Facing wall of your neighboor. He will 
never look at it but you see it all the time.


Thibaud

At 07:36 04-01-2004, you wrote:
I have a nice, south-facing room.  The trouble is, my neighbor's two-story 
house is about 10 feet away, due south.  Consequently,  if I cut an 
aperture in my wall, the sun would find it only mid-summer.  The rest of 
the time, my neighbor's roof would block the sun.  Demolishing his second 
story is not an option, he says.


Tom Egan
33.642 N, 117.943 W-


-
Thibaud Taudin-Chabot
52° 18' 19.85 North, 04° 51' 09.45 East, alt. -4.50 m
home email: [EMAIL PROTECTED]


-

Re: Sundial inside a room, but room is inside a canyon!

[Thibaud Taudin-Chabot]

It is not that difficult, mirror the neighbors wall in relation to the 
mirror, so it will be some imaginary wall in Tom's house. The mirror is the 
tip of the gnomon, or a little window whatever you like. The south facing 
dial on the mirrored neighbors wall has to be mirrored back: left and right 
should switched like top and bottom. And that is simply done by rotating 
the whole design around a horizontal perpendicular axis.


Thibaud


At 18:21 04-01-2004, you wrote:

I love it!
If Tom can sell his neighbor on the esthetic upgrade to his house, it's a
great solution.

How does the geometry work out? Would the mirror need to be *very* high,
say, over 2 stories itself? Closer, or farther than Tom's South wall? I
guess the design trick would be to calculate a South-facing dial with a
nodus 10 feet away from the face, and adjust the nodus hieght to fit...

Dave
37.277N 121.966W

On Sun, 4 Jan 2004, Thibaud Taudin-Chabot wrote:

 Tom,

 There is an other solution:
 Put a miiror high on your south facing wall which will reflect the sun on
 your neighboors North wall.
 Design a sundial for that North Facing wall of your neighboor. He will
 never look at it but you see it all the time.

 Thibaud

 At 07:36 04-01-2004, you wrote:
 I have a nice, south-facing room.  The trouble is, my neighbor's 
two-story

 house is about 10 feet away, due south.  Consequently,  if I cut an
 aperture in my wall, the sun would find it only mid-summer.  The rest of
 the time, my neighbor's roof would block the sun.  Demolishing his second
 story is not an option, he says.
 
 Tom Egan
 33.642 N, 117.943 W-

-


-
Thibaud Taudin-Chabot
52° 18' 19.85 North, 04° 51' 09.45 East, alt. -4.50 m
home email: [EMAIL PROTECTED]


-

Re: Sundial bridges

[Thibaud Taudin-Chabot]

The German Patent Office in Munchen is a building enclosing a square of 
about 70x40 meters.
This square is a sundial, the innercorner of the roof of two wings gives 
the shadowmark on the ground.

The homepage of their website has a picture of the pattern:
http://www.dpma.de/index.htm
but I did not find any other pictures on their site.
The best place to look at the sundial is from the topfloor!
Thibaud Chabot

At 22:21 06-10-2003, you wrote:

I am interested in finding out about the use of architecture/engineering
elements acting as sundials, especially as regards bridge construction. I
know that the architect Santiago Calatrava is designing a 'Sundial Bridge'
in Redding, CA , with an inclined tower acting as a gnomon. Do you know of
any other examples of this?

Kind regards,
Megan Paris

-


-
Thibaud Taudin-Chabot
52° 18' 19.85 North, 04° 51' 09.45 East, alt. -4.50 m
home email: [EMAIL PROTECTED]


-

Re: Stained Glass Sundial Website

[Thibaud Taudin-Chabot]

John,
That is a nice piece of work. I saw my name mentioned under projection
dials. Small correction: I am not Canadian, but Dutch and I am living in
the Netherlands.
Thibaud
At 16:06 29-09-2003, you wrote:
Hello All:

Finally Dave Bell and I have finished the
Stained Glass Sundials From Around the World website:
http://advanceassociates.com/Sundials/Stained_Glass

All the information and photos that we've received has been
posted. We've changed things so many times I've lost count.
We've translated references from foreign literature and investigated
information leads as far as we can. Two months ago Dave told me
that we had exchanged about 650 emails about the SGS website; but it's
double that by now I'm sure.

We received photos of both excellent and horrible
quality. I spent countless hours trying to fix the bad ones.
I'm sure some of you will object to the way I have framed the
photographs. Oh well, that's just too bad! Call it artistic
license.

Links to this site can be found all over the internet.
And I know of at least three glass sundial projects that have already
begun because of the site.

I hope you designers will get some business from this.
Let me know if you do. As a reward for designing a
glass sundial, we will put a photo(s) of your dial on the site along with
your website and email address.

I don't think I've ever worked harder on any one project in
my life, so I hope you like it!

thanks

John (and Dave)


John L. Carmichael Jr.
925 E. Foothills Dr.
Tucson Arizona, USA
Tel: 520-696-1709
Email:
[EMAIL PROTECTED]
Sundial Sculptures Website:
http://www.sundialsculptures.com
Stained Glass Sundials Website:
http://advanceassociates.com/Sundials/Stained_Glass

-
Thibaud Taudin-Chabot
52° 18' 19.85 North, 04° 51' 09.45 East, alt. -4.50 m
home email: [EMAIL PROTECTED]

Re: Dialist's Companion

[Thibaud Taudin-Chabot]

John,
You are one of the very few lucky guys who can say that gnomonists and
navigators look the same way ;-)
I hope for you that this might also reflect in the software. A pity that
most of the software makers hardly think about you down unders,
perhaps they should first visit you?
Thibaud
At 01:32 27-09-2003, you wrote:
Fred and Thibaud 
As one of those people who live in the southern hemisphere the convention
of looking south does not work real well up here ;-)) 
When teaching students of architecture solar geometry I used to suggest
the convention of 'Equator facing' to look toward the sun - this deals
with both hemispheres. Now that just leaves the people on the Equator
having to look both ways and up ;-)) 
On Friday, September 26, 2003, at 10:35 PM, Fred Sawyer wrote:

Simply because
dialists tend to look south towards the sun - with hour angle and azimuth
calculated from the sun's meridian position. At this point we don't
have any definite plans for a new version of the program. If we do
an update, 
Best regards 
John Hall 
41.5 South 147.1 East 
/blockquote/x-html 

Re: Dialist's Companion

[Thibaud Taudin-Chabot]

A navigator is not a dialist.
A navigator always wants to know where the North is, that is why North is
upon your maps.
A dialist looks always to the South and is turning left or right from
that direction.
Thibaud
At 07:39 26-09-2003, you wrote:
Why is the sun's azimuth shown as
180 degrees east or west of south, when my Astro Compass and I daresay
navigators work in 360 degrees from north ?
Can the Dialist Compansion show both.



Message date : Sep 25 2003, 08:15 PM 

From : Fred Sawyer 

To : Sundial List 

Copy to : 

Subject : Dialist's Companion 




In a recent response to John Carmichael, I


referred to some capabilities of the Dialist's Companion
program. It seems 

that a number of people where unaware of these features. After
checking 

the Help page, I discovered that we evidently did not document them -
so no 

wonder that they are still a bit mysterious. This will give a
little more 

detail:




If you are at the 

main page of the Dialist's Companion, you can toggle the clock on and
off by 

hitting the End key (part of the home, end, PgUp, PgDn, and arrow
keys 

arrangement). Notice the small box just to the left of the
Julian Date on 

the screen; once you have hit the End key, the rotating line in this
box changes 

to a V - for virtual mode. When in this mode, the clock is off.
You can 

set the date, latitude, etc. as usual, using the D, T, O keys - or
you can 

change the date and time by using the PgUp, PgDn, Ins, Del and arrow
keys 

to step your way through the hours and days. Note that with
each change in 

time or date, all the values are recalculated and remain on the
screen until you 

change the time again. This makes working with calculations
much 

easier.


size=2 

To start the clock 

up again, hit End. Note that the clock progresses again as
before - but it 

picks up where you left off in the calculator mode. So you can
mimic the 

clock's functioning at any time of the day or year. The box to
the left of 

the Julian Date will still show V, meaning you are still in virtual -
not real, 

current mode. To change back to current mode, press Home - this
brings you 

back home to the real world and synchronizes the software with your
computer's 

clock/calendar. Note that the box now changes from V to the
rotating 

line/arrow you are familiar with. Be sure to have the clock
going when you 

hit Home - otherwise the program synchronizes with the clock for only
a split 

second - the clock continues but if you have the program still in
calculator 

mode, it will not change.


size=2 

I hope this helps - 

and perhaps uncovers capabilities that you didn't know the program


had.


size=2 

Fred 

Sawyer

Re: Place de la Concorde

[Thibaud Taudin-Chabot]

at the right side before the entrance.
The obelisk at the left side of the entrance is still there.
Thibaud Chabot

At 12:56 23-09-2003, you wrote:


The Place de La Concorde was constructed under the July Monarchy between 
1936 and 1846 and an obelisk of Ramses II sent back from Luxor by Napoleon 
during his Egyptian campaign was installed there.   The Thebes in the 
inscription clearly refers to the Egyptian city of Thebes, adjacent to 
Luxor.  I can't be sure that the Obelisk came from east of Thebes, but it 
probably did.  That would explain the au levant de Thebes as the origin 
of the obelisk.


Jack



-

Re: Sundial Carpet

[Thibaud Taudin-Chabot]

That sundial is not 1 spot projected on the floor, but the whole sundial 
pattern projected on the floor.

On the floor you only need 1 readingmark, nothing more.

But the shadow of a spot on a window will be very difficult to find on a 
sunlit floor because the light of the sunlit floor is reflecting in every 
direction and also over the shadow spot so that shadow spot will be less clear.
The bright spot of sunlight from a hole in a closed wall/ceiling will 
therefore much easier to find in a relative dark area.


Thibaud Chabot


At 08:40 06-09-2003 -0700, you wrote:

Seriously, it should work fine. For yet another variant, see
E. Roebroeck's projection sundial in the Netherland's, Dial 8 in the
Stained Glass Sundials photopage, linked from
http://tinyurl.com/frf4
Dave-


-

Re: Wall Declination Software

[Thibaud Taudin-Chabot]

Just a practical remark for both of your programs:
You mention the date format  as mm/dd/ and the time format as H:M:S 
AM/PM but the programs accept only the date and time formats as defined in 
the Regional Options of the Control Panel on your PC.

Thibaud Chabot

At 10:20 03-09-2003 -0400, you wrote:

Now that CardinalDirections.exe is running so nicely, it was not hard to
adapt the code to perform calculations for accurately measuring the 
declination of

a vertical wall.  The method is simple, requiring just a carpenter's square
and a watch.  You can check it out by downloading WallDeclination.exe from
www.precisionsundials.com/software.htm.
The method is sketched in the program, and is described in detail in Wall
Declination.doc on the same software page.  As usual, suggestions are 
welcomed.


-Bill
-


-

Re: Stained Glass Sundial Photos

[Thibaud Taudin-Chabot]

there are two different kinds of stained glass sundials possible:

1. the sundial is made in the stained glass itself and there is a 
style/gnomon on the outside. You can read this one from the outside or from 
the inside if the window is translucent enough to disguish yhe shadow from 
the inside.


2. the pattern is in the stained glass. That pattern is projected on the 
floor where you can read the time  dateon the floor by using a fixed 
reading point on the floor. There is no style/gnomon on the outside or 
anywhere else, so that can not be broken.


I guess you are looking for the type1 dial, but you might consider type2.

Thibaud


At 18:18 30-06-2003 -0400, you wrote:

Do any of you have any photos of stained glass sundials that you could
share
with me?

John, there are about 39 stained glass sundials known in the UK, I think
the earliest is dated 1585 and several workers produce such dials today.  A
good few of these are listed in the BSS Register (if you have that) some
with photographs.

Patrick

-


-
Th. Taudin Chabot, home email: [EMAIL PROTECTED]

-

Re: Stained Glass Sundial Photos

[Thibaud Taudin-Chabot]

About the construction/design look in the Compendium vol.1 nr.3 page 6 and 7.
Up till now I have never seen or heard about one using stained glass.
Thibaud

At 08:27 30-06-2003 -0700, you wrote:

Hello all:

I've been considering contacting local stained glass artisans to inform them
of the possibility of making stained glass sundials. I'm sure many of them
would be thrilled to find out that they can make working sundials and would
love to offer them to their clients.  All they need is a little help from a
dialist to do the drawings.

Since a picture is worth a thousand words, I'd like to show them some
photographs of some of these dials, but I don't have any photos.

Do any of you have any photos of stained glass sundials that you could share
with me?

thanks so much,

John

John L. Carmichael Jr.
Sundial Sculptures
925 E. Foothills Dr.
Tucson Arizona 85718
USA

Tel: 520-696-1709
Email: [EMAIL PROTECTED]
Website: http://www.sundialsculptures.com


-


-
Th. Taudin Chabot, home email: [EMAIL PROTECTED]

-

Re: Precise EOT Program

[Thibaud Taudin-Chabot]

Check for the dialist companion on
http://www.sundials.org/publications/dcomp/dcomp.htm

Thibaud Chabot

At 14:14 12-06-2003 -0700, you wrote:

Hello all,

I'm looking for a handy precise program that calculates EOT values in
minutes and seconds at particular times during the day. In other words, I
don't want the average EOT value for the day as found in the printed tabular
EOT values in Mayall  Waugh.  Instead, it would give the exact EOT value at
a particular time during the day.

I've found several EOT calculator programs (applets) on the Current Data
link at sundials.org. Does anybody know if the values given in these applets
are daily averages or precise values?

Thanks for any suggestions.

John

John L. Carmichael Jr.
Sundial Sculptures
925 E. Foothills Dr.
Tucson Arizona 85718
USA

Tel: 520-696-1709
Email: [EMAIL PROTECTED]
Website: http://www.sundialsculptures.com


-


-
Th. Taudin Chabot, home email: [EMAIL PROTECTED]

-

Re: Julian Date and UbiSol

[Thibaud Taudin-Chabot]

American ephemeris' (1961) on page 71 the definition states:

 Julian Day Number which is defined to be 0 for the day starting at 
Greenwhich mean noon on B.C. 4713 January 1st, Julian proleptic calendar.


Thibaud Chabot


At 17:39 26-04-2003 +1000, you wrote:
Anselmo I have a couple of questions about your UbiSol Julian Date (Julian 
Day). The result for 2003/04/26 seems to be at odds with other calculators.


UbiSol = JD 21478.5
Meeus and others = JD 2452755.5

You and other respected references state this date is calculated from 
January the 1st 4173 BC. Meeus in his first edition of Astronomical 
Algorithms on page 59 states this is calculated from '... the 
beginning of the year -4712'


Can somebody please help me with an explanation ?

Confused of Tasmania
41.5 South   147.1 East

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Th. Taudin Chabot, home email: [EMAIL PROTECTED]

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Re: Positively negative results!

[Thibaud Taudin-Chabot]

your question generates an other question for you:
Do you have a complete step by step instruction how to etch a copperplate 
with a sundial pattern?

What materials do we have to buy and how should we use them?

Long time ago I etched sometimes a printed circuit, but I guess that is 
quite different.
I have the impression there will be more people on the list who would like 
to give it a try.


Thiabud Chabot


At 12:36 08-04-2003 +0100, you wrote:

Hi all,
   I have been etching, photo-etching and engraving copper, brass and
bronze for 30+ years now so those processes hold very few surprises for
me.
Until now I have always had stainless steel etched by subcontrators,
mainly  because the mordants usually recommended seem much more hazardous
than the ferric chloride I normally use on the copper based alloys.





-
Th. Taudin Chabot, home email: [EMAIL PROTECTED]

-

Re: Lady wants Polyhedral Dial

[Thibaud Taudin-Chabot]

T²C

At 09:45 17-12-2002 -0700, you wrote:

Hello Dial sellers:

A lady wants to purchase a desktop polyhedral dial for New York but only has
$100 to spend. I told her that her chances of finding one for that price
were slim, but that I would send you her request.

Her name is Esther Ammon at : [EMAIL PROTECTED]

John

John L. Carmichael Jr.
Sundial Sculptures
925 E. Foothills Dr.
Tucson Arizona 85718
USA

Tel: 520-696-1709
Email: [EMAIL PROTECTED]
Website: http://www.sundialsculptures.com


-


-
Th. Taudin Chabot, home email: [EMAIL PROTECTED]


-

Re: How do we call the equinoxes?

[Thibaud Taudin-Chabot]

But our people at down under will call it reverse!
March and September equinox are more general.
Thibaud
At 14:00 27-11-2002 -0700, you wrote:
I like
spring and fall equinox because it's less letters
to carve. My customers always mix up vernal and autumnal.

John

John L. Carmichael Jr.
Sundial Sculptures
925 E. Foothills Dr.
Tucson Arizona 85718
USA

Tel: 520-696-1709
Email:
[EMAIL PROTECTED]
Website:
http://www.sundialsculptures.com

- Original Message - 
From: The Shaws 
To:
sundial@rrz.uni-koeln.de 
Sent: Wednesday, November 27, 2002 12:21 PM
Subject: RE: How do we call the equinoxes?

Art Carlson suggested:
call them the March equinox and the September equinox

What wonderful simple, understandable names.
I'll go for that :-)


Mike Shaw

mailto:[EMAIL PROTECTED]

http://homepage.ntlworld.com/jmikeshaw/

N 53º 21' 24
W 03º 01' 47
Wirral, UK.


-
Th. Taudin Chabot, home email: [EMAIL PROTECTED]

Re: Wall Dec

[Thibaud Taudin-Chabot]

Thibaud Chabot

At 09:06 15-10-2002 -0400, you wrote:

Roger Bailey has adapted my MSworks (or, more aptly, MSdoesntworks)
spreadsheet for finding wall declination to Excel Format.  It is available at
www.precisionsundials.com/software.htm, along with a word document explaining
the method.
-Bill G.
-


-
Th. Taudin Chabot, home email: [EMAIL PROTECTED]


-

Re: Amsterdam sundial

[Thibaud Taudin-Chabot]

Today I finally got the oppurtunity to check the 2 Amsterdam sundials on 
the New Church in the centre of the city.
The churchwall is roughly declining 12° to the east. The big round sundial 
is mounted flat to the wall. So the style of the big dial is pointing to 
the left (seen from below) of the XII mark.
The small sundial is however turned 12° to the west so it becomes a perfect 
south facing sundial.
Standing directly beforebelow the two dials it is easy to see that the 
style of the small one is bent eastwards. It should be perpendicular to the 
dialface which can be deduced from the fact that the bottom mount of the 
style is directly below the XII mark.
The style of the east dialface and the style of the west dialface are both 
missing. I wonder whether they have ever been present.
It is a pity I didn't see the bent style when I made a very nice picture of 
it using the scaffolding when the wall was being cleaned.

Thibaud Chabot


At 07:44 28-07-2002 -0700, you wrote:

Fer

The Amsterdam dial(s) bothered me when I saw it. My memory isn't so good but
it was a cloudy day and I didn't have a watch. But if I remember the dials
showed different times, and their construction was different in style
position and face design.

Do you know somebody in the Dutch Sundial Society that lives in Amsterdam
who could go to the church and get us some photographs?  We need a photo
showing both dials and need to know watch time photo is taken. Or the next
time you're in the big city, you could take a look and settle the debate.

John

John L. Carmichael Jr.
Sundial Sculptures
925 E. Foothills Dr.
Tucson Arizona 85718
USA

Tel: 520-696-1709
Email: [EMAIL PROTECTED]
Website: http://www.sundialsculptures.com
- Original Message -
From: fer j. de vries [EMAIL PROTECTED]
To: sundial sundial@rrz.uni-koeln.de
Sent: Sunday, July 28, 2002 4:04 AM
Subject: Re: Some ideas for constructing sundials


 Hello Valentin,

 Welcome to the list and thanks for your contribution.

 I downloaded your postscript file and calculated a Quadrant sundial.
 In fact these are portable sundials and you may find them in several
shapes.
 The program worked well and thanks for sharing it with us..

 About the Amsterdam sundials:
 You stated:

  The face of a classical sundial is the projection of a SINGLE POINT,
  which is at some distance from the surface (usially flat). Therefore THE
  BASIC POINT OF THE STYLE IS IRRELEVANT !!!

 In fact this is correct, however the Amsterdam sundials are dials with a
 pole style as shadow caster and the dial may be read with the entire line
of
 shadow of that pole style.
 For such dials the pole styles MUST be parrallel, even for a dial in
 Amsterdam and Harare.

 But the remark was that the styles weren't parallel.
 This could be because one of the styles wasn't mounted correct, as stated
 before.

 Another reason can be as it looks like the styles aren't parallel.
 The circular dial in top of the chursh is directly mounted to the wall
which
 wall declines some degrees to the east.
 The smaller dial at another spot of the same wall is a south facing dial
and
 is angled to the wall with the same wall-declination.
 So it might be an optical effect.
 I haven't the correct answer, I just gave a possible reason.

 The smaller dial at this church in fact is a triple sundial.
 It is a rather thick stone on which the south facing dial is drawn and on
 the west and east side of the stone also a sundial is drawn.

 Best wishes, Fer.

 Fer J. de Vries
 mailto:[EMAIL PROTECTED]
 http://www.iae.nl/users/ferdv/
 Eindhoven, Netherlands
 lat.  51:30 N  long.  5:30 E

 - Original Message -
 From: Dr. Valentin Z. Hristov [EMAIL PROTECTED]
 To: sundial@rrz.uni-koeln.de
 Sent: Sunday, July 28, 2002 8:31 AM
 Subject: Some ideas for constructing sundials


  Dear Dialists,
 
 snip




 -


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Th. Taudin Chabot, home email: [EMAIL PROTECTED]


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Re: Amsterdam Sundial

[Thibaud Taudin-Chabot]

into account 1 hour for the summertime and about 45 minutes for the 
combination of length correction to the 15° meridian and the equation of time.

It is made 1722, so Greenwich etc. was not yet known.
Did you also see the smaller sundial that is mounted about 20 meters lower?
Thibaud Chabot

At 22:52 25-07-2002 +0200, you wrote:

We were in Amsterdam last week visiting the Royal Palace. It was noticed that
the large circular vertical sundial on the Church next door was over two 
hours

different from clock time.
Does anyone know why ?
David  UK.


___
Freeserve AnyTime, only £13.99 per month with one month's FREE trial!
For more information visit http://www.freeserve.com/time/ or call free on 
0800 970 8890



-


-
Thibaud Taudin-Chabot
52° 18' 19.85 North, 04° 51' 09.45 East, alt. -3.45 m
home email: [EMAIL PROTECTED]


-

Re: RE: Gaztelainak hitz egiten duzu? (Off topic)

[Thibaud Taudin-Chabot]

Thibaud

At 23:11 21-07-2002 +0200, you wrote:

Hello,

And why not ESPERANTO ?
It's a universal language, not based on the language war, but on human 
comprehension.


Excuse me for this friendly off topic :-)

 Alain R MORY


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Th. Taudin Chabot, home email: [EMAIL PROTECTED]

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Re: Gluing Stainless to Aluminum

[Thibaud Taudin-Chabot]

Try the link http://www.vantico-aandt.com/newco/addexn.html

My experience is a 20cm wide 4 m long copper strip glued to a concrete base 
outdoor in the Netherlands: from +32°C to -20°C. Up till now no problems.


Thibaud Chabot

At 01:23 29-8-2001 -0400, [EMAIL PROTECTED] wrote:

I am consulting on a local sun sculpture which requires that an aluminum
backing be glued to 6 x 24 stainless steel mirrors.  They can't be screwed
on for fear that the screws and holes might distort the mirror, and hence the
image.  The temperature exposure will range from -20 to 120 degrees
Fahrenheit seasonally, and I think that the glue must be able to forgive the
small difference in the metals' coefficients of expansion.

Any recommendations?  Silicon glue, polyurethane, epoxy, or something else?
Thanks-
Bill Gottesman


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Re: Time Zones

[Thibaud Taudin-Chabot]

Thierry wrote:

So it's not France who distinguishes from the rest, but ...UK who are the
sole
 to insist on 'their' GMT time (nowadays called UT).
(I should check for Ireland, but I'm pretty sure they are on WET/WEST too.)

Ireland is on the same timezone at the UK, and so is Portugal. It seems to
me that Spain and France should be the same too, but for their close ties
with the rest of the European mainland. They are both mostly within 7.5° of
the Greenwich meridian.


there are even parts of Spain and France West of Greenwich!


Anyway, timezones don't solve the whole problem. When I lived in England I
did a lot of business with Finland (+2 hours), and France and Germany (+1).
It was difficult to contact colleagues when we needed to. Yes, this was due
to different timezones, but also different office hours. England worked
9-17.30 local with lunch from 12.30 - 13.30, Finland worked 7.30-16.00 local
with lunch from 11.30 to 12.30, France and Germany something else again.
Germany was extra complicated because the factory staff worked different
hours to the operations staff, so there were two sets of times to remember.


It is all a lot easier now with email isn't it?

Thibaud

-
Thibaud Taudin-Chabot
52°18'19.85 North  04°51'09.45 East
home email: [EMAIL PROTECTED]
(attachments max. 500kB; for larger attachments contact me first)

address astrolabe?

[Thibaud Taudin-Chabot]

reproductions of a astrolabe.
The address was:
Georg Kerstensteiner, Isatorplatz 1, 8000 Muenchen 2.
The shop isn't there anymore. Anybody knows where it is now? Do they have a 
website?


-
Thibaud Taudin-Chabot
52°18'19.85 North  04°51'09.45 East
home email: [EMAIL PROTECTED]
(attachments max. 500kB; for larger attachments contact me first)
-
Thibaud Taudin-Chabot
52°18'19.85 North  04°51'09.45 East
home email: [EMAIL PROTECTED]
(attachments max. 500kB; for larger attachments contact me first)

Re: Commercial Offerings

[Thibaud Taudin-Chabot]

A simple reply:
Never accept commercials on a mailinglist.

If you do you cannot control the list
anymore.

One of the reasons of success of all mailinglists as this one
is that it is not cluttered with lots of commercial stuff. You should see
my (snail)mailbox!

Thibaud

At 11:53 22-2-2001 -0500, you wrote:
Dear Friends,

Over the years, I have noted that members of this group have
followed
the usual mailing list etiquette prohibiting posting messages which
have
commercial content.

I wonder how the group feels about opening the forum to allow members
to
post messages offering items or services for sale, or want lists of
things they might wish to purchase. The offerings should be at 
least
loosely associated with sundials. Undue repetition of offers or
requests
would be unacceptable and replies should be made privately - not to
the
list.

We should note that we are protected from ordinary spam by the
requirement that the only messages posted must come from a
subscriber's
own email address.

I, for one, would be interested in being informed of books, dials,
or
tools and other items that I might be able to purchase. 

I hope this message will prompt a discussion. Based on the
consensus,
the final decision should be made by Daniel Roth - our esteemed
Majordomo; and that no commercial messages should be posted until 
he
gives his OK.

The NASS Website
http://sundials.org
has an Artisans category on its
Links page for those who construct sundials for sale. If you make dials
and have a Web page which is not listed, please contact me.

Best regards,

Bob Terwilliger 

-
Th. Taudin Chabot, home email: [EMAIL PROTECTED]
(attachments max 500kB, in case of larger attachments contact me)

Re: Azimuth calculation

[Thibaud Taudin-Chabot]

hundred meters you can easily use the latitide/longitude as if it is a 
rectangular system. If the distances are in the regions of several 
kilometers/miles it will be a bit more complex.


At 16-11-2000 11:03 -0200, you wrote:
-Original Message/Oorspronkelijk bericht--

Hello Friends

It's been a long, long time since I last disturbed you with my novice
questions.
I was just acculating credits do be entitled to ask the following
question
that has more to do with navigation than any other thing:

a) If I am using UTM coordenates, what is the easiest way to calculate
the bearing from point A to point B in the chart;
b) Same questions if  am using latitude and longitude

When using UTM I have come accross a solution that works but I must
confess I hate it because I don't think it is elegant and it takes a lot
of
time so I am sure there must be a better solution.

For the UTM it is much simpler because I can always create a Pythagorean

triangule whose sides are the difference of Northing and Easting of the
points,
so I have three sides and an angle. Now, if I make the origin point the
origen
of a Cartesian system I can find the Azimuth adding together the angle I
found
plus 0, 90, 180 or 270 if the destination point is on the first, second,
third or
fourth quadrant.

I does work, but there must be a simpler way to do it.

If what I have are the geographic coordinates it takes me much more time

with the spherical triangles and I am never sure I've done the right
thing.

I've read some books on celestial navigation and position astronomy. I
can see
the solution is there, but it does not seem I have the expertise to
convert all those
useful information in a simple formula for this specific calculation.

And I feel very unhappy when I have to fill out a couple of pages with
ugly
calculations just to find out an azimuth I can easily find with a GPS or
with
a protactor and a map!

Best regards

- fernando





--
Fernando Cabral Padrao iX Sistemas Abertos
mailto:[EMAIL PROTECTED]  http://www.pix.com.br
Fone Direto: +55 61 329-0206mailto:[EMAIL PROTECTED]
PABX: +55 61 329-0202   Fax: +55 61 326-3082
15º 45' 04.9 S 47º 49' 58.6 W
19º 37' 57.0 S 45º 17' 13.6 W


-
Thibaud Taudin-Chabot
52°18'19.85 North  04°51'09.45 East
home email: [EMAIL PROTECTED]
(attachments max. 500kB; for larger attachments contact me first)

Re: FONTS

[Thibaud Taudin-Chabot]

sundial-font the program FCP3 which can be found at www.high-logic.com
Thibaud

At 14-11-2000 19:21 +, you wrote:
-Original Message/Oorspronkelijk bericht--

Dear Font Experts,
I have now downloaded the 'JSL Ancient Fonts from the Internet.
A quick try shows that they are just great.  Admittedly they are a
little ragged, but that is probably what their creator, Jeff Lee,
wanted to do.  He is trying to re-create old fonts, isn't he?  By the
time the characters were printed, initially from hand cut punches, which
would then be sunk into copper, and the type cast from these moulds,
then when they were printed on hand made paper, I guess that they would
come out roughly as he has shown.

My thanks to Andrew James and John Davis for leading me to these
fonts.
For anyone else who did not note the web address, here it is
again:-

http://www.gate.net/~shipbrk/typograf.html

Regards,
Mike.
[EMAIL PROTECTED]
Cambridge, UK.


-
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(attachments max 500kB, in case of larger attachments contact me)

Re: A Sundial as a Prize

[Thibaud Taudin-Chabot]

-Original Message/Oorspronkelijk bericht--

Chuck Nafziger contributed:

In regards to finishes friendly to shadow definition: matte white is my
choice.

I don't think anyone could disagree with that.


Well, you might consider a slightly darker colour like sand or beige. My 
experience is that when you use white the shadow will be less sharp because 
the white colour is also reflecting some sunlight. I found this when I 
noticed that the shadow on a dark brown surface seemed to be better visible 
than the shadow on a white surface


Thibaud

-
Thibaud Taudin-Chabot
52°18'19.85 North  04°51'09.45 East
home email: [EMAIL PROTECTED]
(attachments max. 500kB; for larger attachments contact me first)

Re: A Sundial as a Prize

[Thibaud Taudin-Chabot]

-Original Message/Oorspronkelijk bericht--

 ... A photo of a dial similar to the one made for Patrick Moore can
 be seen on the internet at
  http://www.lindisun.demon.co.uk/smallest.htm

I have a question for Tony Moss about the dial pictured.  Unless there
is another scale on the back we can't see or the dial plate can be
turned over, this dial can only be used in summer.  That's OK, but
then why do you include the Equation of Time for the whole year?

--Art Carlson


You have to turn over the scale only for use in the southern hemisphere. In 
order to read the other side: put the dial on a mirror.
Toni: I see the gnomon being refelcted on the surface. My experience is in 
that case that it is rather difficult to read the shadow instead of the 
refelxion. I suggest to mat the surface slightly to increase the readability.

Thibaud


-
Thibaud Taudin-Chabot
52°18'19.85 North  04°51'09.45 East
home email: [EMAIL PROTECTED]
(attachments max. 500kB; for larger attachments contact me first)

Re: Act of 1752

[Thibaud Taudin-Chabot]

The year 1800 wouldn't be a leap year under the Gregorian calendar because
18 is not a mutliple of 4. Would England have adopted the Gregorian
calendar right from the start in 1582 then 1600 would have been the first
centennial leap year.
Did you know that by the same act of Parliament in 1751 the start of the
year was changed from 25 March to 1 Januari, commencing in 1752 ?

At 16:03 15-11-99 -0700, you wrote:
-Original Message/Oorspronkelijk bericht--
Wouldn't it be more accurate to say that the treatment of 1800 as a
normal year was a result of the Gregorian reform in England and her
colonies, but not the treatment of year 2000 as a leap year?  Under
both Julian and Gregorian systems 2000 would be a leap year.

Furthermore, the treatment of 1800 as a normal year was not the first
effect of the legislation.  September 1752 was very interesting, as
demonstrated by the UNIX cal program

   % cal 9 1752
  September 1752
S  M Tu  W Th  F  S
  1  2 14 15 16
   17 18 19 20 21 22 23
   24 25 26 27 28 29 30

Jim40N45, 111W53
=-=
Do not condemn the judgment of another because it differs from your
own.  You may both be wrong.   -- Dandemis

Frank Evans wrote:
 Greetings fellow dialists and calendrists,
 
 A note about the millennium leap year that I recently came across in the
 journal History Today:  When the next leap day arrives, on 29 February
 2000, it will be, for Britain, the result of the adoption of the
 Gregorian calendar in 1752.  By then most other European countries had
 already embraced the new calendar. The Act of Parliament which causes
 this first centenial leap year since then to take place was passed 248
 years and 3 months ago.  Is this the longest delayed action legislation
 ever?  By the way, the 1752 Act also applied to the UK Colonies
 including America (no offence intended).
 
 Frank  55N 1W
 -- 
 Frank Evans

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Thibaud Taudin-Chabot
52°18'19.85 North  04°51'09.45 East
home email: [EMAIL PROTECTED]
(attachments max. 500kB; for larger attachments contact me first)

Re: Sundials not needing corrections

[Thibaud Taudin-Chabot]

At 16:03 13-5-99 -0400, you wrote:
-Original Message/Oorspronkelijk bericht--
Mac Oglesby wrote:

  a dial to indicate
 relative sunburn danger.  Installed at a swimming pool or beach, this type
 of dial wouldn't even need any hour lines - regions of color would alert
 the sunbather as to when (s)he would burn most rapidly.


Ross McCluney replied:

As an optical/solar physicist, I was intrigued by this, and the possible
errors
in its use.  As long as the sunbather is in a horizontal position, and not
particularly concerned about sunburn on the sides, just on the top, one
could
have a vertical post gnomon with concentric circular rings around it, giving
zones of angle of incidence upon a horizontal plane.  With the sun
highest in

(snip)


Hi Ross,

Thanks for your thoughtful response.  Most of what you wrote hadn't
occurred to me - but then I never seriously considered making such a dial
myself.  I guess that if a sunburn dial were installed in any public
place, extensive disclaimers would need to accompany it.  Imagine that - a
dangerous sundial!

Mac

This kind of disclaimers are only found in the USA
and on products from the USA ;-)

-
Thibaud Taudin-Chabot, home email: [EMAIL PROTECTED]
(attachments max 500kB, in case of larger attachments contact me)

Re: Magnetic compass

[Thibaud Taudin-Chabot]

As far as I understood the main reason for using sun compasses in the
Sahara was that a magnetic compass would be rather unreliable on those
moving masses of steel called tanks during WW2.

At 08:04 24-3-99 +1000, you wrote:
-Original Message/Oorspronkelijk bericht--
Folks,

Roger's comment re sun compasses is correct and also applies 
partially to Antarctica.

Up to at least the 1970s, ANARE (Australian National Antarctic 
Research Expeditions) used surplus military Astro Compasses on 
over-ice traverses.

When I wintered at Davis Station 68o 35' S 78o 00'E, we used 
magnetic compasses ALL the time. All I had to do was remember that 
the deviation was 78o W (I think it was west!). At times, this caused 
some interesting discussions about directions!

Altho the large deviation was inconvenient, it was not really a 
problem.

Of course, GPSs have ended all that! 

John


Dr John Pickard
Senior Lecturer, Environmental Planning
Graduate School of the Environment
Macquarie University, NSW 2109 Australia
Phone + 61 2 9850 7981 (work)
  + 61 2 9482 8647 (home)
Fax   + 61 2 9850 7972 (work)


-
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Re: dead reckoning

[Thibaud Taudin-Chabot]

I never realised that the names of the navy watches were different on the
British ships. Dutch Navy has the following scheme:
00.00-04.00 Hondewacht (Dogwatch, only dogs are supposed to be awake)
04.00-08.00 Dagwacht (Daywatch, the watch were you can see the first daylight)
08.00-12.00 Voormiddag wacht (Ante Meridian watch)
12.00-16.00 Achtermiddag wacht (Past Miridian watch)
16.00-18.00 Eerste platvoetwacht (First Flatfood watch)
18.00-20.00 Tweede platvoetwacht (Second Flatfood watch)
20.00-24.00 Eerste wacht (First watch)

So you see that in the Dutch Navy they split the watch around evening
dinnertime into two half watches.

The term dutchman's log is not a translation but means the cheapest log
available. 

Bye the way, did you ever see a sundial on a ship? The Dutch cruiseship
Oranje had one. The ship sank after a fire long ago(I think in the pacific)
so we cannot check it anymore.






At 14:50 14-2-99 +, you wrote:
-Original Message/Oorspronkelijk bericht--
Greetings, fellow dialists,

Just a further very brief word on dog watches.  On British ships, and
I'm sure everywhere else, dog watches were two half watches, each of two
hours.  They were from four till six and six till eight in the evening.
Their purpose was to change the daily watch order aboard watch and watch
ships, once universal.  On British merchant ships they were called first
and second dog watch while in the Royal Navy they were called first and
last dog watch.  I think Thibaud Taudin-Chabot and Slawek Grzechnik are
both mistaken in thinking these watches occurred in the night.  The
watch from midnight to four in the morning is called the middle watch, a
watch I once knew well.

Interesting that the Dutch have a 'hondewacht'.  This must be the same
word as dog watch.   Is 'honde' just a modifier?  We had another example
a moment ago with 'dutchman's log' (also 'dutch log'), which is not a
real log but a bit of wood chucked over the side and timed past two
points on the ship's length.  It is very accurate at low speed.

Message to sundialists.  Please be patient and stop pushing.  Sundials
will return to these pages soon.  Watch this space.

Frank

-- 
Frank Evans

-
Thibaud Taudin-Chabot, home email: [EMAIL PROTECTED]
(attachments max 500kB, in case of larger attachments contact me)

Re: Toys for boys (AND girls!)

[Thibaud Taudin-Chabot]

I have such a compass for about 20 years. It is a great and very handy
compass and very accurate.
But be careful! If you are wearing glasses that are fitted in a metal frame
you can get a misreading of up to 5 degrees because the compass is very
close to the frame depending on the kind and amount of metal.
I found this by pure accident in a case where I knew what readings I should
have when I demonstrated the compass to a friend.




At 08:47 13-2-99 -0800, you wrote:
-Original Message/Oorspronkelijk bericht--
Boys (AND girls!)

My new toy arrived, that is Mini Avio 2000 Compass that I could not help
but order on the night I was replying to compass related postings. It is
absolutely lovely and very easy to use. It is marine compass filled with
liquid and they do not mention anything about its resistance to low
pressure so I will not take it to the mountains. On the other hand they
probably ship those by air and cargo compartments probably are not
pressurized so who knows.

As a marine compass it has rotating compass rose rather than magnetic
needle. Its optical system is a prism-lense single piece of glass focused
at infinity. So during bearings you keep the thing to your cheek and look
at the object while seeing the appropriate part of the rose in the prism
and take very accurate reading.

So if you have about $100 to spend do not hesitate. Celestaire sells French
made ones but I think other companies sell similar pieces as well. If you
cannot spend $100 at this time then the best solution is $10 Scandinavian
make. Do not take the ones with mirrors but the simpliest ones and learn
how to use them efficiently.

Slawek


Slawek Grzechnik
32 57.4'N   117 08.8'W
http://home.san.rr.com/slawek

-
Thibaud Taudin-Chabot, home email: [EMAIL PROTECTED]
(attachments max 500kB, in case of larger attachments contact me)

Re: sunset times

[Thibaud Taudin-Chabot]

How about the dip angle which is there because your eye is not at ground
level and the calculations think you are!

Dipangle(in minutes of arc)=1.06*SQRT(ht in feet)
Dipangle(in minutes of arc)=1.92*SQRT(ht in meters)

I guess this will help you

Thibaud Chabot

At 15:55 30-1-99 +, you wrote:
-Original Message/Oorspronkelijk bericht--
Hi John and others in the golden west,

You make the case that the sun truly sets earlier than it appears to do.
If, as you say, 34 minutes of arc represents 2.26 minutes of delayed
sunset time due to refraction, we are getting into seconds.  In that
case we must do what the Nautical Almanac does not, and consider the
height of the observer's eye.

The late Mr. E.W. Barlow, a meteorologist in the British Met. Office
once told me that while serving aboard one of the ocean weather ships he
saw the green flash (visible under very clear conditions at the moment
of sunset) three times at a single setting.  This he said he achieved by
moving to successively higher decks as the sun went down.

Pondering this, I have reckoned that if the decks were, say, ten feet
apart he would have about four seconds to move from one deck to the
next.  I wonder if, being prepared, such a feat would be possible and
whether anyone else has ever attempted it.  Or was he just hauling my
leg?
Frank


-- 
Frank Evans

-
Thibaud Taudin-Chabot, home email: [EMAIL PROTECTED]
(attachments max 500kB, in case of larger attachments contact me)

Re: Radius of the Earth

[Thibaud Taudin-Chabot]

At 12:18 3-8-98 +0100, you wrote:
-Original Message/Oorspronkelijk bericht--
Fellow Shadow Watchers,
   Information boards are being prepared for a
nearly-completed large dial on a hill near the Northumberland (UK) coast
which is 94 metres above mean sea level at Latitude  55° 1' 38 North
Longitude  1° 30' 16 West. 

 The latest question is How far away is the sea horizon?  School
geography taught me that the earth is an 'oblate speroid' so I suppose the
true distance varies slightly depending on the direction in which the
observer is looking but so little as to be unimportant perhaps?  The sea is
only visible in a generally easterly direction.

Can any list member supply the mean sea level radius of the earth at this
location on which to base the necessary trig calculation plus any
subtleties I may have overlooked as I don't have ready access to specialist
reference material of this sort.

With thanks in anticipation of any helpful response.

Tony Moss

Tony,
I saw already some nice formulas for the calculations. However your
starting point is constant changing: your heigth is 94 meters above mean
sea level you say. So that is only 4 times a day. All other moments your
height above the actual water level will be more or less thanm the 94
meters! Each meter more or less changes the distance to the horizon by ca.
0.1 nautical miles.
Is that heigth of 94 meters at ground level or is it the heigth of the eye
of the observer?
How much is the difference between high tide and low tide at that spot? In
Britain the sea-levels are related to the Chart datum, which usually
approximates to Mean Low Water Springs (which occurs roughly once a month).
Normally a sailor doesn't have to take this into account because he floats
on the water, but you have a fixed observationpoint on the land.
I am afraid you have to make a few corrections to the 94 meters!
The refraction is dependant on the airpressure and the temperature.

-
Thibaud Taudin-Chabot, home email: [EMAIL PROTECTED]
(attachments max 1.2MB, in case of larger attachments contact me)

sundial in Central Park, New York

[Thibaud Taudin-Chabot]

Entering Central Park from 5th Av at 72nd St. and turning immediately right
you find a bench with a model of a roman hemispherical sundial in the back
of the bench. NASS refers to it as item #0250.
At the bottom the this semicircular bench there are also lines with
inscriptions which give the suggestion that there should be somewhere
another gnomon. Is it gone or did I overlook something? Who knows more
about it?
Thiabud Chabot
-
Thibaud Taudin-Chabot, home email: [EMAIL PROTECTED]
(attachments max 1.2MB, in case of larger attachments contact me)

Re: Time Zone Names

[Thibaud Taudin-Chabot]

I checked that page. 
When I was in the (Dutch) Navy we were living in Alpha zone. According the
table I am now living in November zone. Also in my time zone Juliet did not
excist.

I checked my (old) books and there it was:
'Zones to the eastward are letterd A to M (J is omitted), those to the
westward being letterd N to Y.'
(Admirality Manual of Navigation, Vol I, 1970, page 359)

Are those names changed in the meantime?



At 09:26 20-6-98 -0700, you wrote:
The following page has names for most time zones.

http://time.greenwich2000.com/time/info/timezone.htm

There also is a Unix file tzname which I think has three-letter codes
to support Unix time functions.  I have not used it.

Gordon

At 08:53 AM 6/20/98 -0400, Ross McCluney wrote:
Tony Moss has a wall chart produced by the Admiralty giving time zones
around the world.  It is too large to reproduce.  I would consider
purchasing one, but it is incomplete, since it doesn't have the names of
all the zones. 


-
Thibaud Taudin-Chabot, home email: [EMAIL PROTECTED]
(attachments max 1.2MB, in case of larger attachments contact me)

another sundial in Munich?

[Thibaud Taudin-Chabot]

Today somebody told me which made me think that he described some kind of
sundial. It should be in a (public) passage in the European Patent Amt in
Munich Germany. (Not the one in the German Patent Amt!). I checked the book
'Sonnenuhren Deutschland und Schweiz' (1974 edition) but could find it.
Somebody knows about it? 
---
Thibaud Taudin Chabot,  email: [EMAIL PROTECTED]

from New York - student and sundial

[Thibaud Taudin-Chabot]

-- Forwarded message --
Date: Thu, 18 Dec 1997 21:18:50 -0500
From: Arnold Michael [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Cc: [EMAIL PROTECTED]

Dear Ms. Weeg and Mr. Bell,
  Hello.  I am an eighth grade student participating in the Earth
Science Regents Course for New York State.  One of the things we must do
in order for the Regents exam at the end of the year is make a long term
investigation project relating to earth science.  I have decided to make
a wooden sundial and use its observations to make a presentation
comparing electronic time (clocks) to natural time (sundials).  If you
could, please send me any ideas, comments or information you might have
that would be useful in my project to:

Lori Kalikstein
86 Bayne Place
White Plains, NY 10605
[EMAIL PROTECTED]

 Thank you for your time and help.


 Sincerely,
   Lori Kalikstein

---
Thibaud Taudin Chabot,  email: [EMAIL PROTECTED]

Re: Simulating Sunlight

[Thibaud Taudin-Chabot]

At 11:03 28-11-97 -0800, you wrote:
Seattle's long and rarely sunlit winter has begun in earnest. I'm
experimenting with building dials and want to test the ability of different
gnomon designs to cast shadows. 

Does anyone have ideas on building simulated sources of sunlight? I'm
guessing a reasonable approximation is to simply put a bright light in a
tube, and choose the appropriate tube diameter and distance from the dial
so that the angular size appears near 32 minutes. Or do you need lenses to
make the light appear more parallel? Maybe my old slide projector could do
the trick with some modifications.

The well-stocked gnomonicist should probably have such a tool regardless of
available sunlight! This is especially the case if the person's dials of
choice include those that are sensitive to seasonal variations.

Thanks,

Tom

In the Technical University of Delft in the Netherlands there is a solar
simulator. It can be used by architects using a small model of their
building(s).
The basic construction is so elegant that I think it might help you:

The model can be placed upon a table. This table can turn around its
vertical axis: a scale on the edge will give you the azimuth.
With this table in the centre they constructed a vertical quarter of an arc
(from the 'horizon' up to the 'zenith'). Along this arc there is a light
source which is always pointed to the centre of the table. A scale along
this arc will give you the heigth of the sun above the horizon.

This construction can be handdriven, the values of azimuth and heigth can
be read easily. At the university they coupled the lightsource along the
arc as well as the turning of the table to stepmotors which are connected
to a computer. A simple program handles all possibilities.

The most important possibilities I saw were:
1. Every place on the earth could be used, North and South;
2. During a day the movement of the shadow of a model could be observed
along with a time indicator.
3. A time could be fixed and the movement of the shadow could be observed
during a year with a date indicator.

I have checked a sundial for the Southern hemisphere on it and it worked
perfect!

As lightsource they use a lamp with a large parabolic reflector which came
from a searchlight out of Worldwar II.

Hope this idea helps you.

---
Thibaud Taudin Chabot,  email: [EMAIL PROTECTED]

Re: Foster sundials.

[Thibaud Taudin-Chabot]

At 05:06 22-09-97 -0500, you wrote:
Hi Mac and all,

Mac Oglesby wrote:
 
 Hi Warren,
 
 C'mon, you can't leave us hanging like this!  Give a hint, at least, about
 the appearance of the Italian hour lines on a Foster-Lambert sundial.
 Please.
 

My first thoughts:
If you can make a Foster/Lambert dial with a vertical gnomon, why not
one with a horizontal gnomon?  To picture these we would think of moving
a F/L dial north or south along the meridian to a location where the
gnomon is the angle we want for our latitude. For a horizontal gnomon,
set the zero hour on the horizon, level with the gnomon.  As the gnomon
is moved up or down for different declinations of the sun, the zero hour
on a movable ring would also be turned to be level with the horizon. 
More than 12 hours would show in the summer and fewer than 12 hours in
winter.  Would the back of the ring need to be marked also? The last
question that remains is at what angle is the hour ring with repect to a
horizontal gnomon? With (G=(90+L)/2) or (G=(90-L)/2) do we use L for our
latitude or for a new latitude?  If a new latitude, what is it?

Comments are appreciated.
Happy Dialing,
Warren

Warren,
I don't get it. A horizontal gnomon can only indicate the heigth of the
sun, just like a vertical gnomon can only give you the azimut.

---
Thibaud Taudin Chabot,  email: [EMAIL PROTECTED]

Re: Foster-Lambert-sundial

[Thibaud Taudin-Chabot]

At 17:35 13-09-97 +0200, you wrote:
Dear all

Search for Foster-Lambert-Sundials !

Please let me know where there are Analemmatic Sundials of
the Foster-Lambert-Type. By that I am referring to stationary
sundials.

As of now I know of only one stationary Foster-Lambert-Sundial :

Switzerland, CH-4132 Muttenz, Canton Basel-Land,
Engeneering school.

I would be grateful for any information.

Best regards
Karl Schwarzinger
Austria
[EMAIL PROTECTED]


Could you describe the dial? 
---
Thibaud Taudin Chabot,  email: [EMAIL PROTECTED]

Re: Yvon Masse - response re. Inclination/Declination

[Thibaud Taudin Chabot]

At 00:53 20-06-97 +, you wrote:



The letter and program listing from Yvon Masse enabling the calculation of
Declination and Inclination of a plane in QBasic makes me wish there was
something similar written in OPL for the Psion 3C palmtop.  As a very new
owner of this little wonder I'm not yet familiar enough to attempt anything
like this for myself and wonder if anyone out there has already done so?

Tony Moss

You can also try to make a spreadsheet.
---
Thibaud Taudin Chabot,  email: [EMAIL PROTECTED]

Toscane dials

[Thibaud Taudin Chabot]

In about a week I will visit Toscane for ca. 7 days. Can anyone tell me if
there are sundials in Toscane which I have to visit because they are so
special.
---
Thibaud Taudin Chabot,  email: [EMAIL PROTECTED]

Re: Sun's Declination

[Thibaud Taudin Chabot]

At 06:18 29-03-97 EST, you wrote:
Dear Angelo,

 I need to know how to calculate, with a good accuracy,  the sun
 declination for April 18 1693.

According to the Dialist's Companion, the sun's declination on 4-18-1693 was
11.234 degrees.  This was at noon on the prime meridian.

The Dialist's Companion will calculate information such as this from 1
A.D. to 2999 A.D., and is available at:

http://www.shadow.net/~bobt/dcomp/dcomp.htm

Best regards,

Bob Terwilliger
NASS Design and Construction Group

Watch out!
I guess April 18 1693 is in the Gregorian Calendar? If located in Italy it
will be.
Not every country switched fro the Julian calandar to the Gregorian
Calendar on October 5 1582, e.g Great Britain did it on September 3 1752
and Switzerland did it partly in 1584 and partly in 1701.
These dates can be found in 'Explanatory Supplement to the Ephemeris'
published by HMSO in London, pages 414-416.

---
Thibaud Taudin Chabot,  email: [EMAIL PROTECTED]

Astr Meeus

[Thibaud Taudin Chabot]

I have a program Astro Meeus, ver.0.9. Once found somewhere on the
Internet, but forgot where. Does anybody know where and if there is a later
version?
---
Thibaud Taudin Chabot,  email: [EMAIL PROTECTED]

Re: Wish list for a new home.

[Thibaud Taudin Chabot]

At 05:40 01-03-97 -0600, you wrote:
This thread poses some interesting possibilities.

If you could design a unique home,  what special locations might
a person consider for windows, floor, halls, and rooms so that sunlight
would show in special ways?  

For example, my home faces southwest, and on Christmas day the sun
sets directly in front.  Our tree can be 6 meters from the window
and get sunlight that afternoon.  In June, the back of my home gets
the direct sunrise light. (except I have a large shade tree blocking
it.)

 fer j. de vries wrote:
 [EMAIL PROTECTED] wrote:
 determine the projections for extremal values of Sun's zenith (for 
each of 365 days, or some other, fewer interval) -- that would give 
the area COVERED by the sunlight -- then the solution is everything 
OUT OF IT.  

Some deleted

 A mathematical methode how to calculate a plane sundial is on my
 homepage
 http://www.iaehv.nl/users/ferdv/
 Click English and than the page to compute sundials.

Some deleted

 This makes the problem a little more complicated.
 In the horizontoscoop this is directly visible.
 Fer J. de Vries, Netherlands.

Indeed, a horintoscope is the right instrument for this kind of problems. I
also use it to find out which tree has to be cut and which branches.
The horintsope is produced by:
'Institut fuer Tageslichttechnik'
Rob. Koch strasse 116
Stuttgart
Germany.
(postal code unknown to me, the old one was 7000, but they changed it to 5
digits in Germany)

---
Thibaud Taudin Chabot,  email: [EMAIL PROTECTED]

Re: Clock setting

[Thibaud Taudin Chabot]

At 21:46 07-01-97 +1000, you wrote:
Hi all
   Just remembered that: On the clocks mailing-list someone said 
that there is a new quartz watch that now has a receiver built inside it 
to receive WWV or WWW (don't know which).  The receiver is used to set 
the watch to the correct time. The only problem is that it will not work 
in Australia. If anyone is interested I will ask the clocks mailing-list 
where this watch can be obtained from.

Roderick Wall.
___
Roderick Wall
E-mail: [EMAIL PROTECTED]
Melbourne Australia.


Those watches are available in Europe and they are tuned to the DCF77
timesignal transmitter. This transmiiter is located in Germany (near
Frankfurt am Main) and is using  a frequency of 77.5 kHz and has ca. 20kW
power. Because of this low frequency the station can reach an area of ca.800km.
I have no experience with these watches.
There are many models of table/alarm clocks using DCF77 available in Europe.
The brand name of Jungerhans is a well known one. I even saw the chips for
receiver and decoder in a catalog.
Thibaud Taudin-Chabot [EMAIL PROTECTED]

Re: Holey Calendar, Dateman! Was: Equation of time

[Thibaud Taudin Chabot]

At 15:55 30-12-96 -0800, you wrote:
Well, I started to join in in the EoT calculation fun,
following Francois Blateyron's original question. I began
by implementing his equations in a spreadsheet, as he did.
I used Microsoft Excel... 

With Robert Sinnott's correction to the longitude of perihelion
calculation, I was getting a close fit, but still not quite
on. Today, I started to implement Paolo Gregorio's posting
of the algorithm from the Explanatory Supplement. Well, heck,
all I need do is add the necessary offset to Excel's intrinsic
date function (based on 1/1/1900 = 0), and I have Julian Date.
Piece of cake. 
Right.

Until I notice a one day difference from (Excel) calculated
JDate to that from The Dialist's Companion by Bob Terwilliger
and fred Sawyer of NASS.

Not to be stopped, I grabbed an old copy of the BASIC algorithm
from Sky and Telescope's Astronomical Computing (May 1984), and
coded that in Excel Visual BASIC. Well, *that* date agrees
with the Dialist, so what's wrong with Excel??

A little troubleshooting led to the hitherto unknown fact that
1900 really *was* a leap year. At least according to Excel!

Is this a known bug? Certainly something to be aware of, anyway!
Not to mention that the date computations only support the
range of 1/1/1900 = D = 12/31/2078...

Dave Bell


Watch out! Yes this is a known bug in Excel. I had a long discussion with
Microsoft about it.  They didn't think it worth mentioning because only
people like us have difficulties with it.
Excel is starting to count at 0 Jan 1900. So day 1 (not 0) is 01 Jan 1900.
Check which date day 60 is. You can do that by putting 60 in a cell and
format this cell as representing ddmm. You run the risk that you will
see 29Feb1900, which is a non existing date (1900 was not a leapyear, 2000 is!).
You can avoid this bug by using the so called 1904 date system. This option
in Excel can be found under Tools Options. In that case Excel starts
counting at 0 jan 1904, so you have to add a number of days to get the
proper Julian day: 4*365=1460 days.
Another difficulty is that in Excel the daynumber changes at modnight, 00:00
hrs. A Julian day number changes at midday Greenwichtime, so at 12:00 hrs.GMT.
Thibaud Taudin-Chabot [EMAIL PROTECTED]

Re: A request

[Thibaud Taudin Chabot]

At 09:55 12-11-96 +0100, you wrote:

 I think there is a large horizontal dial with curves for the equation of
time 
 at a financial bank in Munich, Germany.
 The point where two walls of the building meets is used as the shadow casting
 device.
 I have no idea how high this point is, nor do I know how large the dials
 plane is.

This sundial is located at the 'Deutsches Patentamt'. The dial plane is about
30 times 60 meter. But I have no information about the height of the shadow
caster.

- Daniel Roth, Arbeitskreis Sonnenuhren

As far as I can remember this cornerpoint was situated on the 5th or 6th
floor, I am not sure anymore. Actually it is the corner in the gutter. I
guess the heigth to be around 15 meters. I didn't have to climb the stairs
because there was a very old and stil perfectly working paternoster elevator
system in the building. 
The best of seeing this sundial is asking if you are allowed to see it from
a window from the topfloor. It is a master piece.
Thibaud Taudin-Chabot [EMAIL PROTECTED]

Re: sundials in navigation

[Thibaud Taudin Chabot]

As far as I know sundials were not used in navigation, unless you call an
astrolabe or quadrant a sundial. These were the old instruments used in
navigation.
Finding North using sundials isn't very accurate, especially not between
10:00 and 14:00. The farther the time is away from noon the more acurate it
can be done. However if you want to do that on a (sailing)ship you need a
very stable platform that remains perfectly horizontal. If not your
horizontal sundial will be of no use. I have never seen a stable horizontal
platform on a sailing ship except during periods of no wind and no waves at
all (this is very seldom at sea).

Thibaud Taudin-Chabot
[EMAIL PROTECTED]


At 10:59 09-09-96 PDT, you wrote:
Are there references to the use of sundials in navigation?  
In the days before magnetic variation was mapped, they must have been useful
(with the limitations of stability that a dial on board a ship would have.)
No doubt travellers on land used them, are there special types that
developed  for this purpose?
Also, does anyone know how accurately these dials are at orienting to
north?   They seem to have the advantage that they don't have to be
adjusted for magnetic declination and that they aren't affected by
other magnetic fields.  (And of course the obvious disadvantage that
they must have sun in order to work.)  So, they seem like they would
be a great companion to a compass.

  Peter Abrahams[EMAIL PROTECTED]
the history of the telescope, the microscope,
   and the prism binocular

Re: Almost a South Pole Sundial

[Thibaud Taudin Chabot]

At 15:46 22-08-96 -0700, you wrote:
Slawek Grzechnik ([EMAIL PROTECTED]) wrote:

 I think that sundials for the new Millenium should be set on the poles.
 Imagine how simple the dial and the style would be. Each of them would be
 working half a year


A dial at the South Pole *almost* exists.

About 18 months ago I corresponded with Bob Loewenstein, of the University
of Chicago's Center for Astrophysics in Antarctica (CARA), querying him
about the ceremonial South Pole marker: a barber-pole-like structure
surmounted by a small reflective dome.  Encircling it, at a few-meters
radius, are the national flags of the researchers encamped at Amundsen-Scott
South Pole Station.  (To see a photo, check out _Sky and Telescope_,
December, 1982, page 520.)

I was curious to learn if someone had already thought to space the flags at
15-degree intervals, and to offset them so they'll function as hour markers
for a particular time zone -- hence creating a horizontal/equatorial sundial
(and the only one of its kind simultaneously in both categories).  Bob
replied that nobody had seen fit to set up the flags with a sundial in mind.
(Though, I was hoping my question would inspire this simple modification
when Bob departed for his next several-month stint there.)  Bob did point
out, however, that most of the researchers quickly learned how to tell time
by noting the Sun's azimuth.

Here's an interesting trivia question: What is the adopted time zone at
the South Pole Station?  Since they could choose any time zone they like,
I assumed they'd use Universal Time -- but this turns out not to be the case.
In fact, they use the same time zone as New Zealand -- even mimicking the
Kiwis' habit of changing from/to Summer Time (which is odd, since polar
residents don't derive any benefit from time shifting when the sun is
perpetually above the horizon in the austral Summer).  The rationale for
this is logistical: South Pole Station is serviced regularly by a support
crew flying out of Christchurch, New Zealand; by keeping New Zealand time,
there's no risk of time-conversion errors resulting in a missed rendezvous
or communication.

~~
 Mark Gingrich  [EMAIL PROTECTED]  San Leandro, California
~~

A few months ago I was involved in a KIDLINK project with a school in
Delmam, Marylamd U.S.A. where a few childeren had to make a sundial for
McMurdo base on the Antartic. I designed a analemmatic sundial for 90S which
will be a circle with every 15degr. a marker. This was easy to explain and
understand by the childeren. The shadow of a person standing in the centre
was used to read the time.
As McMurdo station is actually located at 78S I also calculated the
differences between the designed sundial and a proper calculated analemmatic
sundial at 78S. The maximum differences in angular measurements were 1
degree and in placement of the markers a maximum of 56 millimeters occured.
As these differences were so small I declared the simple sundial designed
for  the South Pole at 90S valid for McMurdo staion at 78S.
I don't know whether the sundial is ever made. I don't think so because it
is now winter and hardly any sun at McMurdo.
 
Thibaud Taudin-Chabot [EMAIL PROTECTED]

sundial designed by Richard L. Schmoyer

[Thibaud Taudin Chabot]

I am looking for the universal sundial which was designed by Richard L.
Schmoyer years ago.

It was published in Scientific American and has a very special kind of style
which is curved to compensate for the equiation of time. Even a device for
changing to Daylight Savings time is made. It is constructed in such a way
that it can be installed anywhere on the world.

If possible I would like to acquire one because it is the sundial which
started my interest for sundials.

In the past 20 years I wrote to him 3 times but I never got any reply.

Who can help me?

Thibaud Taudin-Chabot [EMAIL PROTECTED]

Star Grasper

[Thibaud Taudin Chabot]

I would like to know whether it is still possible to get one 'The Star
Grasper or Astrolabe' as was designed by Mr. Harold N. Saunders. ( I am NOT
looking for the 'Universal Astrolabe' from the same author).
Thibaud Taudin-Chabot [EMAIL PROTECTED]