Return the Sidereal Time (in hours) from Latitude and Longitude

import ephem from math import radians, degrees, cos, sin, asin, pi ##------------------------------------------------------------------------- ## Sidereal Time ##------------------------------------------------------------------------- # Author: Inaki Ordonez-Etxeberria # # Return the Sidereal Time (in hours) from Latitude and Longitude of the observatory, and date of observation. If the parameters are empty, the function assumes the position of the Isaac Newton Telescope in La Palma, at the moment of execution of the function. def SiderealTime(lat = '28.775867', lon = '-17.89733', date = 'now'): observatory = ephem.Observer() observatory.lon = lon observatory.lat = lat observatory.elevation = 2328 if date == 'now': observatory.date = ephem.now() else: observatory.date = ephem.Date(date) return degrees(observatory.sidereal_time()) / 15