That was a good thought to prepare that resume on the web, I could read it
in peace.
It gave me some thinking and I put down my thoughts so other people might
come to new ideas.
A polar dial which reads civil time and constructed with one dial/style is
not possible because the datescale on sundial is in fact a declination
scale. For each declination there are two dates involved so there are two
different timeequation values involved. John stated already no analemmas,
so it has to be a single line for two different corrections. Sorry, I think
that is indeed not possible.
But.... why not make two polar dials, each with a different pattern. One
for the summer/autumn and one for the winter/spring.
It might even be the same polar dial with interchangeable
gnomon/style/shadowwire.
Take the dial constructed by W. Bits: each our line can be shifted with the
longitude correction and a slight additional shift for the timeequation. Do
this for summer/autumn. Then calculate bachwards how the wire should be in
winter/spring. If these two different two wires are used in the correct
period the polar dial should read civiltime, or make two polar dials with
fixed wires.
Anybody who thinks this might be possible?
Thibaud Chabot
At 16:08 07-01-2003 -0500, you wrote:
7 Jan 03
Hello Friends,
On December 29 I mistakenly sent to the entire sundial mailing list a
message intended for one member, Dave Bell. In that message I asked Dave
if he would be willing to post some materials I had collected concerning
the problem of finding a shaped gnomon to give civil time directly on a
polar dial.
Due to a misunderstanding on my part, I announced that such a gnomon had
been designed about 20 years ago. Alas, we still are looking for a
solution. If you have any interest in seeing a report on our search so
far, point your browser at
http://advanceassociates.com/Sundials/A_Civil-Time_Polar_Dial/
or, for slow typists
http://tinyurl.com/46ss
Dave Bell has provided the space, and has taken the time and trouble to
set up the webpage. I greatly appreciate his assistance with this web
posting. But any errors are my responsibility, so contact me if you find
mistakes. General comments are also welcome.
I wish to thank John Close for raising the question, to thank all those
who contributed to the material posted, and I extend a special thank you
to my good friend Fer de Vries for providing the quoted text.
Best wishes,
Mac Oglesby
P.S. Please let the sundial list members know if any of you have other
information to share concerning this problem.
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Thibaud Taudin-Chabot
52° 18' 19.85" North, 04° 51' 09.45" East, alt. -4.50 m
home email: [EMAIL PROTECTED]
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