Send sundial mailing list submissions to
[email protected]
To subscribe or unsubscribe via the World Wide Web, visit
https://lists.uni-koeln.de/mailman/listinfo/sundial
or, via email, send a message with subject or body 'help' to
[email protected]
You can reach the person managing the list at
[email protected]
When replying, please edit your Subject line so it is more specific
than "Re: Contents of sundial digest..."
Today's Topics:
1. Calculating the Equation of Time and other Solar Parameters
(Kevin Karney)
2. CORRECTION Calculating the Equation of Time and other Solar
Parameters (Kevin Karney)
3. Re: Calculating the Equation of Time and other Solar
Parameters (Bill Gottesman)
4. online manuscript by Mayall and Mayall (Schechner, Sara)
5. Re: Calculating the Equation of Time and other Solar
Parameters (Roger Bailey)
----------------------------------------------------------------------
Message: 1
Date: Sun, 23 Feb 2014 19:32:37 +0000
From: Kevin Karney <[email protected]>
To: "[email protected] List" <[email protected]>
Subject: Calculating the Equation of Time and other Solar Parameters
Message-ID: <[email protected]>
Content-Type: text/plain; charset="windows-1252"
Dear Friends
I have spend many happy hours during this wet, wet winter investigating and
learning how to calculate all the solar parameters that a gnomonist might
possibly need - Equation of Time, Declination, RA, Altitude, Azimuth, Time of
Sunset/Rise, etc, etc.
I have been surprised to find that - with traditional calculation methods and
an absolute minimum of astronomical information - it is possible to calculate
everything from first principles to a surprising degree of accuracy.
Other than location and local time, only six pieces of astronomical information
are required - obliquity, eccentricity, Sun?s GHA at 1/1/2000, longitude of
perihelion, a single precessional constant and the length of the tropical year.
Accuracies for the EOT are +/- 2 seconds of time For altitudes/azimuths, less
than 1 minute of arc - much better than needed by most gnomonic problems.
If any of you are interested in such calculations, I have loaded a document
with all the astronomical theory and background plus the code onto my website
www.precisedirections.co.uk/sundials
The code is written in Python, a language available on every type of computer,
which is very easily understood, quite easily learnt and very easily translated
into any other coding language you might like.
If you own an iPad or iPhone, and are prepared to buy a cheap little app called
Pythonista, the code will extract locational & time information from your phone
- so you do not even have to input this to get your calculations done
You might also like to see a graphic of a civil mean time horizontal dial,
which I think is called a hectomoros dial, that is destined for my garden.
This is also on the website.
Enjoy
Kevin
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<https://lists.uni-koeln.de/mailman/private/sundial/attachments/20140223/b50a01bb/attachment-0001.html>
------------------------------
Message: 2
Date: Sun, 23 Feb 2014 20:06:51 +0000
From: Kevin Karney <[email protected]>
To: "[email protected] List" <[email protected]>
Subject: CORRECTION Calculating the Equation of Time and other Solar
Parameters
Message-ID: <[email protected]>
Content-Type: text/plain; charset="windows-1252"
My website is ?
http://www.precisedirections.co.uk/Sundials
with a capital S for Sundial
Sorry
K
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<https://lists.uni-koeln.de/mailman/private/sundial/attachments/20140223/75ac7917/attachment-0001.html>
------------------------------
Message: 3
Date: Sun, 23 Feb 2014 15:52:57 -0500
From: Bill Gottesman <[email protected]>
To: Kevin Karney <[email protected]>
Cc: "[email protected] List" <[email protected]>
Subject: Re: Calculating the Equation of Time and other Solar
Parameters
Message-ID:
<CAMDsn==32iapzw47q7zo4-wwyxbcttzcjcjax+y8vvtv_fd...@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
Kevin,
I am excited about your article "Basic Astronomy for the Gnomonist." It
will take some time to digest, but it seems to have a very nice graphic
analysis for the many formulas and solar positioning we deal with. I
appreciate you making this reference available.
I think what you call a Hectoromos dial is what I have heard described as a
Singleton dial. Here is a link to a similar (vertical) dial at the
University of Vermont. Fred Sawyer wrote about the Hectoromos dial in an
early NASS compendium. I think Plato might have had something to do with
it.
-Bill
On Sun, Feb 23, 2014 at 2:32 PM, Kevin Karney <[email protected]> wrote:
Dear Friends
I have spend many happy hours during this wet, wet winter investigating
and learning how to calculate all the solar parameters that a
gnomonist might possibly need - Equation of Time, Declination, RA,
Altitude, Azimuth, Time of Sunset/Rise, etc, etc.
I have been surprised to find that - with traditional calculation methods
and an absolute minimum of astronomical information - it is possible to
calculate everything from first principles to a surprising degree of
accuracy.
Other than location and local time, only six pieces of astronomical
information are required - obliquity, eccentricity, Sun's GHA at 1/1/2000,
longitude of perihelion, a single precessional constant and the length of
the tropical year. Accuracies for the EOT are +/- 2 seconds of time For
altitudes/azimuths, less than 1 minute of arc - much better than needed by
most gnomonic problems.
If any of you are interested in such calculations, I have loaded a
document with all the astronomical theory and background plus the code onto
my website
*www.precisedirections.co.uk/sundials
<http://www.precisedirections.co.uk/sundials>*
The code is written in Python, a language available on every type of
computer, which is very easily understood, quite easily learnt and very
easily translated into any other coding language you might like.
If you own an iPad or iPhone, and are prepared to buy a cheap little app
called Pythonista, the code will extract locational & time information from
your phone - so you do not even have to input this to get your calculations
done
You might also like to see a graphic of a civil mean time horizontal dial,
which *I think* is called a hectomoros dial, that is destined for my
garden. This is also on the website.
Enjoy
Kevin
---------------------------------------------------
https://lists.uni-koeln.de/mailman/listinfo/sundial
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<https://lists.uni-koeln.de/mailman/private/sundial/attachments/20140223/ecf6e400/attachment-0001.html>
------------------------------
Message: 4
Date: Sun, 23 Feb 2014 21:29:20 +0000
From: "Schechner, Sara" <[email protected]>
To: "Sundial List ([email protected])" <[email protected]>
Subject: online manuscript by Mayall and Mayall
Message-ID:
<5739be999e14ea4c97335684ddae402d0d1d8...@harvandmbx04.fasmail.priv>
Content-Type: text/plain; charset="us-ascii"
Dear All,
As those who attended last summer's meeting of the North American Sundial
Society know, I have done some research on the Margaret Mayall and R. Newton
Mayall, authors of the well-known, Sundials: How To Know, Use, and Make Them,
and their connections to sundials presently in Harvard's Collection of
Historical Scientific Instruments. My research paper has not yet been
published.
One of the manuscripts I have used was a typescript catalog of the Ernst
Collection by the Mr. and Mrs. Mayall. The document is held at the Harvard
College Observatory. It was recently digitized and is now available online.
You can find it here:
The Harold C. Ernst Collection of Portable Sundials
Mayall, R. Newton
Mayall, Margaret W.
http://zenodo.org/record/8326
Best wishes,
Sara
Sara J. Schechner, Ph.D.
David P. Wheatland Curator of the Collection of Historical Scientific
Instruments
Department of the History of Science, Harvard University
Science Center 251c, 1 Oxford Street, Cambridge, MA 02138
Tel: 617-496-9542 | Fax: 617-496-5932 |
[email protected]<mailto:[email protected]>
http://scholar.harvard.edu/saraschechner/
http://chsi.harvard.edu/
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<https://lists.uni-koeln.de/mailman/private/sundial/attachments/20140223/76f16be7/attachment-0001.html>
------------------------------
Message: 5
Date: Sun, 23 Feb 2014 15:48:53 -0800
From: "Roger Bailey" <[email protected]>
To: "Kevin Karney" <[email protected]>, <[email protected]>
Subject: Re: Calculating the Equation of Time and other Solar
Parameters
Message-ID: <F7EE14E0C34B4B4BB91DADFD6E444B9D@DellVista>
Content-Type: text/plain; charset="windows-1252"
Thanks Kevin,
A quick review demonstrated how useful your work can be for folk like us. Here
is a specific example. I have been working with solar and lunar ephemerides
date from the JPL Horizons website. http://ssd.jpl.nasa.gov/horizons.cgi#top
This site provides a wealth of data that the user can customize for their own
purposes. The problem is the user does not know how the data was calculated nor
how it is to be used The Explanatory Supplement helps but it is difficult to
understand. One simple example is understanding a solar data compilation that
provided among other things Right Ascension and Declination. But I really
wanted the EQT. Your formula 9 in Part 1 gave me the simple relationship,
obvious in hindsight that I was looking for, the conversion of RA to EQT.
I look forward making good use of your work. Thank you for making it available.
Thanks again,
Roger Bailey
Walking Shadow Designs
From: Kevin Karney
Sent: Sunday, February 23, 2014 11:32 AM
To: [email protected] List
Subject: Calculating the Equation of Time and other Solar Parameters
Dear Friends
I have spend many happy hours during this wet, wet winter investigating and
learning how to calculate all the solar parameters that a gnomonist might
possibly need - Equation of Time, Declination, RA, Altitude, Azimuth, Time of
Sunset/Rise, etc, etc.
I have been surprised to find that - with traditional calculation methods and
an absolute minimum of astronomical information - it is possible to calculate
everything from first principles to a surprising degree of accuracy.
Other than location and local time, only six pieces of astronomical information
are required - obliquity, eccentricity, Sun?s GHA at 1/1/2000, longitude of
perihelion, a single precessional constant and the length of the tropical year.
Accuracies for the EOT are +/- 2 seconds of time For altitudes/azimuths, less
than 1 minute of arc - much better than needed by most gnomonic problems.
If any of you are interested in such calculations, I have loaded a document
with all the astronomical theory and background plus the code onto my website
www.precisedirections.co.uk/sundials
The code is written in Python, a language available on every type of computer,
which is very easily understood, quite easily learnt and very easily translated
into any other coding language you might like.
If you own an iPad or iPhone, and are prepared to buy a cheap little app called
Pythonista, the code will extract locational & time information from your phone
- so you do not even have to input this to get your calculations done
You might also like to see a graphic of a civil mean time horizontal dial,
which I think is called a hectomoros dial, that is destined for my garden.
This is also on the website.
Enjoy
Kevin
--------------------------------------------------------------------------------
---------------------------------------------------
https://lists.uni-koeln.de/mailman/listinfo/sundial
--------------------------------------------------------------------------------
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4335 / Virus Database: 3705/7118 - Release Date: 02/23/14
-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4335 / Virus Database: 3705/7118 - Release Date: 02/23/14
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<https://lists.uni-koeln.de/mailman/private/sundial/attachments/20140223/822876d9/attachment.html>
------------------------------
Subject: Digest Footer
_______________________________________________
sundial mailing list
[email protected]
https://lists.uni-koeln.de/mailman/listinfo/sundial
------------------------------
End of sundial Digest, Vol 98, Issue 3
**************************************
