utils.py 文件源码

def stupidFast_altAz2RaDec(alt, az, lat, lon, mjd):
    """
    Convert alt, az to RA, Dec without taking into account abberation, precesion, diffraction, ect.

    Parameters
    ----------
    alt : numpy.array
        Altitude, same length as `ra` and `dec`. Radians.
    az : numpy.array
        Azimuth, same length as `ra` and `dec`. Must be same length as `alt`. Radians.
    lat : float
        Latitude of the observatory in radians.
    lon : float
        Longitude of the observatory in radians.
    mjd : float
        Modified Julian Date.

    Returns
    -------
    ra : array_like
        RA, in radians.
    dec : array_like
        Dec, in radians.
    """
    lmst, last = calcLmstLast(mjd, lon)
    lmst = lmst/12.*np.pi  # convert to rad
    sindec = np.sin(lat)*np.sin(alt) + np.cos(lat)*np.cos(alt)*np.cos(az)
    sindec = inrange(sindec)
    dec = np.arcsin(sindec)
    ha = np.arctan2(-np.sin(az)*np.cos(alt), -np.cos(az)*np.sin(lat)*np.cos(alt)+np.sin(alt)*np.cos(lat))
    ra = (lmst-ha)
    raneg = np.where(ra < 0)
    ra[raneg] = ra[raneg] + 2.*np.pi
    raover = np.where(ra > 2.*np.pi)
    ra[raover] -= 2.*np.pi
    return ra, dec