projector.py 文件源码

def galToCel(ll, bb):
    """
    Converts Galactic (deg) to Celestial J2000 (deg) coordinates
    """
    bb = numpy.radians(bb)
    sin_bb = numpy.sin(bb)
    cos_bb = numpy.cos(bb)

    ll = numpy.radians(ll)
    ra_gp = numpy.radians(192.85948)
    de_gp = numpy.radians(27.12825)
    lcp = numpy.radians(122.932)

    sin_lcp_ll = numpy.sin(lcp - ll)
    cos_lcp_ll = numpy.cos(lcp - ll)

    sin_d = (numpy.sin(de_gp) * sin_bb) \
            + (numpy.cos(de_gp) * cos_bb * cos_lcp_ll)
    ramragp = numpy.arctan2(cos_bb * sin_lcp_ll,
                            (numpy.cos(de_gp) * sin_bb) \
                            - (numpy.sin(de_gp) * cos_bb * cos_lcp_ll))
    dec = numpy.arcsin(sin_d)
    ra = (ramragp + ra_gp + (2. * numpy.pi)) % (2. * numpy.pi)
    return numpy.degrees(ra), numpy.degrees(dec)