> What's the energy penalty for pointing the PV array off Sun- > > dead-center, at say 1 arc-second, 1 arc-minute, etc...? Sine of angle ~+ angle for small values of angle. Closish at even 10 degrees. So subtended panel area drops with eror_angle/90 for smallish angles. Russell --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .