Backtracking angle calculator

Flat ground, horizontal north-south axis, endless rows, direct beam only. Angles are east positive (morning); pvlib prints the same angle with the opposite sign. Presets use illustrative inputs. It does not estimate energy.

True-tracking angle

GCR (0.05 to 0.95)

Rotation limit (degrees, 10 to 90)

Latitude (degrees, -65 to 65)

Declination (degrees, -23.5 to 23.5)

Solar time (hours, 0 to 24, e.g. 7.5)

True-tracking angle (degrees, -90 to 90)

Sun elevation-

True-tracking angle-

Backtracking starts beyond-

Backtracking angle (no limit)-

Rotation applied (with limit)-

Shaded share if held at the limit, no backtracking-

Shade-free check, backtracked-

Beam factor, cos(angle gap)-