How to determine if it is daytime (light outside?) in python using ephem library -

How to determine if it is daytime (light outside?) in python using ephem library -

the ephem python library can determine next sunrise , sunset.

what want know if lite outside or not @ moment in time. there simple function phone call in ephem returns this?

organizations united states of america naval observatory have definitions “it lite outside” — can find usno’s definitions here:

http://aa.usno.navy.mil/faq/docs/rst_defs.php

once take definition want, inquire sun object alt , compare value height in definition usno. recommend utilize alt, fast pyephem compute. if instead inquire sunrise , sunset, sent pyephem off on expensive iterative search has maintain trying different times of day until discovers moment of sunrise , sunset — not interested in, sounds like. want compare sun's height own threshold “is lite outside.”

note alt in radians, need convert chosen number of degrees before comparing:

import ephem

s = ephem.sun() sf = ephem.city('san francisco') s.compute(sf) twilight = -12 * ephem.degree print 'is lite in sf?', s.alt > twilight

python light pyephem