steradian…
A graphical representation of two different steradians.
The sphere has radius r, and in this case the area A of the highlighted spherical cap is r. The solid angle Ω equals [A/r] sr which is 1 sr in this example. The entire sphere has a solid angle of 4π sr.
…
General information…
Unit systemSI
Unit ofsolid angle
Symbolsr
Conversions…
1 sr in …… is equal to …
SI base units1 m/m
square degrees⁠180/π⁠ deg
≈ 3282.8064 deg

(echo:: @ ᯤ)