A square degree (deg2) is a non-SI unit measure of solid angle. Other denotations include sq. deg. and (°)2. Just as degrees are used to measure parts of a circle, square degrees are used to measure parts of a sphere. Analogous to one degree being equal to π/180 radians, a square degree is equal to (π/180)2 steradians (sr), or about 1/3283 sr or about 3.046×10−4 sr.
|Unit of||Solid angle|
|1 deg2 in ...||... is equal to ...|
|SI units||3.04617×10−4 sr|
The whole sphere has a solid angle of 4πsr which is approximately 41253 deg2: