astro.py 文件源码

def gmst(lod, jul_day):
    '''Computes smoothed Greenwich siderial time:
    http://articles.adsabs.harvard.edu//full/1982A%26A...105..359A/0000360.000.html'''
    tut1 = (jul_day - 2451545.0) / 36525.0
    seconds = -6.2e-6 * tut1 * tut1 * tut1 + 0.093104 * tut1 * tut1 + \
        (876600.0 * 3600.0 + 8640184.812866) * tut1 + 67310.54841
    _theta = 2 * pi * fmod(seconds / 86400.0, 1.0)
    theta = _theta if _theta > 0 else _theta + 2*pi
    omega = 7.29211514670698e-5 * (1.0 - lod / 86400.0)

    return theta, omega