The above question was "How can I calculate the solid angle that a sphere of radius R subtends at a point P?"
and was closed for being "too localized". But since I can answer it , I could perhaps present the answer here.
The desired formula for d>R or d=R is 2*pi*(1-K) where K is the non-negative square root of (1-((R/d)^2)) and
d is the distance between the sphere's center and P.