Tilt angle and row spacing

How it is calculated

Solar geometry on 21 December (winter solstice, declination −23.44°) in solar time: at 12:00 the sun is due south; clock time may differ by half an hour to an hour. The sun's altitude h and azimuth A from south are computed every 5 minutes of the chosen window. The north–south shadow of a row's top edge = H · cos A / tan h, where H = length along the slope · sin α. Row pitch = length along the slope · cos α + the longest shadow, rounded up to 10 mm. Length along the slope = panels × panel side + 20 mm between panels, as in the designer. Flat ground, rows facing south. The optimal tilt is the annual-yield maximum of the designer's model (a fit over latitude). The designer spaces tables by the noon sun — the “noon only” option.