The suns position is specified as altitude and azimuth from the
observers position.
This can be computed from the Declination and Right Ascension of the sun
if you know the current local sidereal time and the latitude.
Then you have to adjust the altitude to compensate for the refraction of
light through the atmosphere.
On 2011-08-23 22:29, Donald Christensen wrote:
I need to write a spreadsheet to find the sun position. I know there are
already many programs that do this. However, I need to write one myself
because:
1. I'll learn as I write
2. It will give the sun position in the format that I need
3. I can tweak the spreadsheet to give the same answer but in another
format.
My question is, where do I start?
I want to input
Latitude
Longitude
Time
The sun position will then be in X Y Z coordinates.
I'll back up. I'm drawing a sundial in Autodesk Inventor. I can place
lights that represent the sun. I can move the lights while I film my
animation and watch the shadows move.
That's why I need the sun position in XYZ format. I want the shadows
accurate. I don't need the sun to be 150,000,000 km away from my
sundial. It only needs to be 100 meters away
I want to first write it to output azmith and altitude. (or the same as
other programs whatever the output is) I'll then tweak my spreadsheet to
convert this to XYZ
--
Cheers
Donald
0423 102 090
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So there!
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