Joe said: > I'm working on a solar tracker and would like to calculate the
sunrise/sunset position. The aim is to use a PIC controlling a
pair of steppers and gear trains

One algorithm frequently cited is this one

http://williams.best.vwh.net/sunrise_sunset_algorithm.htm

/>
__________

I have a friend who is highly expert in this - he may be willing to comment

Peripheral thoughts

Do you want to do this? eg

- will your panel rotate past +/- 90 degrees as it needs to d for full
tracking?

 When the sun is very low, are you better off pointing the panels at it
through the local hills, trees, houses etc (no) or would you get slightly
better results by pointing it at some sky location that has at least a
glimmer of light in it (yes, but there will still be very little energy).

See eg  http://www.gaisma.com/en/location/auckland.html for

eg in mid summer the sum is behind a north facing observer before 0930 and
after  1700
The sun is above the horizon from about  0558? to 2039 at that time.
You wont get much energy from 0558 to 0930 or for 1700 to 2039 - but you'll
probably get more from the sky than eg from a row of houses.


 Russell McMahon
--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.