Hi Mac et al,
You are, of course, completely right - you can turn a polar dial around its
gnomon to make allowance for the EoT - my humble apologies. It isn't intuitive
(to me, at least) that this should work and I foolishly made my comment without
experimenting or doing the maths. I have
Hi Dave,
A while ago you offered to post sundial material on your website
(since we can no longer send attachments of any appreciable size to
Sundial List members. Does that offer still stand?
I have received some information showing how a 3-D gnomon (though not
a solid) can be (and has
PM
Subject: Re: 3-D gnomon for Polar Dial
Hi Dave,
A while ago you offered to post sundial material on your website
(since we can no longer send attachments of any appreciable size to
Sundial List members. Does that offer still stand?
I have received some information showing how a 3-D
Hello John Davis and sundial list members,
I think I should give a short comment since I worked on this problem
(or at least on a closely related one) years back. I quote from the
mail of John Davis.
The solution, I think is the suggestion of Fer de Vries to use the polar dial
designed
is the question actually?
Regards, Frans
53.1N. 6.5E
- Original Message -
From: Mac Oglesby [EMAIL PROTECTED]
To: Sundial Mail List sundial@rrz.uni-koeln.de
Cc: John Close [EMAIL PROTECTED]
Sent: Monday, December 09, 2002 3:21 PM
Subject: 3-D gnomon for Polar Dial
Hello All,
John Close has
direction slightly every day (or
every few days) to account for EoT. Some dialists feel that a pivoted
polar is no longer a polar, but that's a different problem, for
polar dial seems to have some different meanings, depending on what
source is consulted.
A 3-D gnomon on a polar dial would cast
P.S. Bill Gottesman has sketched a possible solution and has given
permission to share. Contact me OFF LIST if you want a copy of his
drawing (16K gif).
I would like to see that drawing, Mac!
I can imagine how such a gnomon would work and might look, but believe it
would need to be split
direction slightly every day (or
every few days) to account for EoT. Some dialists feel that a pivoted
polar is no longer a polar, but that's a different problem, for
polar dial seems to have some different meanings, depending on what
source is consulted.
A 3-D gnomon on a polar dial would cast
, but that's a different problem, for
polar dial seems to have some different meanings, depending on what
source is consulted.
A 3-D gnomon on a polar dial would cast a wavy shadow on the flat
dial plate, and civil time could be read where that shadow crossed a
straight line of hour
On Mon, 23 Dec 2002, Mac Oglesby wrote:
With respect, I have to disagree with John Davis. If you rotate a
polar dial around its polar axis (or any axis parallel to the
Earth's--an edge of the dial plate, for instance)
(Which of course, IS rotation about the gnomon axis, PLUS translation in
Hi,
I haven't seen any reply to the John Close / Mac question. Did I miss
something? What's the verdict?
For my part, I can see that it would be possible to construct a 2D shape
(approximately oval), which when set in equatorial plane, would cast a
shadow giving a certain EoT adjustment - you
But wait a minute
...as soon as I'd sent my last message, I saw a problem with it.
The plane of the sun's orbit doesn't really change with declination, so my
way out of the problem of varying declination doesn't work - so I don't have
a solution after all!
Steve
-
Mac Oglesby recently asked:
John Close has posted this message on the NASS Message Board:
Does anyone have any ideas for a Polar Dial which allows for an
Equation of Time adjustment. I would not like analemma shaped hour
lines as I think this would detract from the simplicity and
Mac Oglesby recently asked:
John Close has posted this message on the NASS Message Board:
Does anyone have any ideas for a Polar Dial which allows for
an
Equation of Time adjustment. I would not like analemma shaped
hour
lines as I think this would detract from the simplicity and
Hello All,
John Close has posted this message on the NASS Message Board:
Does anyone have any ideas for a Polar Dial which allows for an
Equation of Time adjustment. I would not like analemma shaped hour
lines as I think this would detract from the simplicity and
minimalistic quality of a
:[EMAIL PROTECTED]]
On Behalf Of Mac Oglesby Sent: Monday, December 09, 2002 9:22 AM
To: Sundial Mail List Cc: John Close Subject: 3-D gnomon for
Polar Dial Hello All, John Close
has posted this message on the NASS Message Board: "Does anyone
have any ideas for a Polar Dial which a
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