def _azimuth2math(azimuth, elevation):
 theta = np.radians(((90 - azimuth) % 360))
 phi = np.radians((90 - elevation))
 return (theta, phi)

def _azimuth2math ( azimuth , elevation ) : theta = np . radians ( ( ( 90 - azimuth ) % 360 ) ) phi = np . radians ( ( 90 - elevation ) ) return ( theta , phi )
converts from clockwise-from-north and up-from-horizontal to mathematical conventions .