Dear John:
attached is the table you've asked for. It includes the astronomical year,
the month, day, and time of the event, and azimuth (in degrees) of sunrise
and sunset. Azimuth is measured from North towards East (so North = 0
degrees, East = 90, South = 180, West = 270).
The table is based on
, June 26, 2012 3:25 PM
To: John Pickard; Sundial Mailing List; Roger Bailey
Subject: Re: Calculating azimuth of sunrise and sunset from present back 25,
000 years
Dear John:
attached is the table you've asked for. It includes the astronomical year,
the month, day, and time of the event, and azimuth
Hello David,
I recognized my error in the middle of the night, long after pressing the
send button. 150 m is still locally significant. Over millions of years
these forces move mountains and continents.
Regards, Roger
--
From: David Patte ?
Hello Frank and all,
You raise an interesting point . At first I thought that we should not
confuse human time, 25,000 years with geological time, 25 million years.
Then I reconsidered. We tend to think in terms of the Rock of Ages, solid
enduring and unmoving, not considering the geological
If I'm not mistaken:
25,000 x 6 mm = 150,000 mm = 150m, not 1500m
Did you mean cm?
On 2012-06-25 0:11, Roger Bailey wrote:
At this time I am moving 6 mm per year towards the east, as determined
by precise GPS and laser surveys. Over 25,000 years this movement is a
mile, 1.5 km and a lot of
Dear John:
I may be able to help. I can write a custom program that would generate the
data you are asking for. There is a glitch, however, and that is the
accuracy of the models to be used over such a long period of time. In
particular, I would use the following models:
(a) VSOP87D for the
To get a small indication of the variation that occurs over long periods of
time, you could try the excellent, easy to use and free Horizons program from
JPL-NASA. It will take you back to 3000 BC. That's a step on the way to 25000
years.
The program has a good web interface. Just google JPL
Good evening on a chilly Winter Solstice in Sydney,
As part of my research on fences, I need to calculate the azimuth of sunrise
and sunset back to 25,000 y ago. The question arises from the disputed origins
of some dry stone walls found in southern New South Wales. A local historian
has
