The angle of incidence of sunlight on a stationary flat panel would be a
sinusoidal curve between sunrise and sunset but I don't think the power
output would quite follow the Rule of 12ths. For one thing the amount of
atmosphere the light has to pass through would squeeze the peak output
towards the center where both the filtering and the angle of incidence would
be least. If the panel were mounted so it tracks the sun the output curve
would be flatter.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Geoff Schultz" wrote in message
.. .
Does the hours of sunlight follow the rule of 12ths? I suspect that it
does, but I'm too busy to figure it out by myself and I thought that
someone might now the answer off the top of their head.

-- Geoff