 
Hi:
I noticed that you're making use of my page "Focus-Balanced Paraboloidal Reflector". That's good. I'm glad that somebody is finding it useful.
You might also be interested in this:
http://www.appropedia.org/Sun_related_calculations
Let me know if you have any questions.
DOwenWilliams 15:15, March 14, 2012 (UTC)