The Sun and Moon both subtend a solid angle of 5 11 10 6 sr in the sky of Earth or about 1 2 500 000th of the celestial sphere Could this be wrong Using the formula provided an answer of 5 98 10 5 is given Another web based article appears to be correct The sun and moon are both seen from Earth at a fractional area of 0 001 of the celestial hemisphere or 5 98 10 5 steradian 1