Shadow Designs
From: Robert Terwilliger
Sent: Wednesday, December 07, 2016 6:34 AM
To: sundial@uni-koeln.de
Subject: New York Times - Today will be the earliest sunset of the year.
http://www.twigsdigs.com/annex/sunset.html
Bob
http://www.twigsdigs.com/annex/sunset.html
Bob
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https://lists.uni-koeln.de/mailman/listinfo/sundial
Is there a name for the day on which the earliest sunset occurs? I know it
varies with latitude unlike the solstice.
Cheers,
John
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https://lists.uni-koeln.de/mailman/listinfo/sundial
An excellent article on this is:
Wagon, Stan. Why December 21 Is the Longest Day of the Year Mathematics
Magazine, Vol. 63, No. 5, December, 1990, pp. 307-311.
Mathematics Magazine is a journal of the Mathematical Association of America
(MAA) and is available in most all college libraries in
Earliest sunset is around 12 dec., but the latest sunrise is around 30 dec.
Combining the two gives the shortest day at 21 dec.
Thibaud Taudin-Chabot [EMAIL PROTECTED]
in sunset and that the earliest sunset is not at
the winter solstice.
So I told my uncle this, and the family got down to accomplishing other
life-tasks. Unfortunately, I recently realized that this explanation
must be false. This came about by looking more closely at an analemma on
a globe. If I
Greetings All,
I've been trying to figure this one out myself since here on Guam, the
sun starts setting later in November and continues rising later until
February, so we don't have a shortest day. Well, that's not true, the
shortest days of the year on Guam are all even numbered days
Jack Aubert,
Your question was : 'Why the earliest sunset is at 13 dec'?
Only looking to the aspect of the declination of the sun in december the
length of a day wil shorten so the sun will set earlier each day till
about 21 december. From then the length of the days will increase
is independent of the sun's declination,
except via E. The earliest sunset will occur when E is largest. This
happens around 3 November.
If we re-do the calculation for Los Angles, with latitude of about 34
degrees, we find that the earliest sunset occurs around 6 December. Note
that we have
One thing to keep in mind: the zero point of the Equation of Time is
*not* arbitrary, but comes from the shape of the analemma (or equivalently
from the shape of the earth's orbit and orientation of its north pole).
The Equation of Time is the difference between apparent solar time
(tied to the
According to my Soda Can Dial, the earliest sunset appears to be around 11 Dec
(at least for Washington, D.C.) and the latest on July 2. I don't know if that
is true everywhere (in fact, I doubt it).
Brad
I would like to forward the following enquiry to all those dialiasts
who know more than I do about celestial mechanics. It seems to me
that the answer has something to do with the fact that the sun appears
as a disk rather than a point in space, but I don't know enough to think
this through
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