Jan 24, 2020 · Calculate Sunrise and Sunset based on time and latitude and longitude. This is a modification of the sunrise.c posted by Mike Chirico back in 2004. See the link below to find it. I needed an algorithm that could tell me when it was dark out for all intents and purposes.

*Jul 11, 2015 · I'm not sure if this is in the right forum but I assume someone in charge can move move it if it's not. Anyway, is there an equation or algorithm or something I can use to calculate the sunrise/sunset times at a given latitude/longitude on a given day of the year (or possibly something that...*necessarily when its hour angle is ±90°. The hour angle at sunset or sunrise, HS, can be found from using Eq. (7) when β1 = 0 )cos(HS ) =−tan(L)tan(δ (8) where HS is negative for sunrise and positive for sunset. Absolute values of cos(HS) greater than That depends on where you are (longitude and latitude). You can use the Sunrise/Sunset Calculator at the U.S. Naval Observatory's web site, at the link below, to calculate the time of sunrise and ...