def sun_ra_dec(utc_time):
    """Right ascension and declination of the sun at *utc_time*.
    """
    jdate = jdays2000(utc_time) / 36525.0
    eps = np.deg2rad(23.0 + 26.0 / 60.0 + 21.448 / 3600.0 -
                     (46.8150 * jdate + 0.00059 * jdate * jdate -
                      0.001813 * jdate * jdate * jdate) / 3600)
    eclon = sun_ecliptic_longitude(utc_time)
    x__ = np.cos(eclon)
    y__ = np.cos(eps) * np.sin(eclon)
    z__ = np.sin(eps) * np.sin(eclon)
    r__ = np.sqrt(1.0 - z__ * z__)
    # sun declination
    declination = np.arctan2(z__, r__)
    # right ascension
    right_ascension = 2 * np.arctan2(y__, (x__ + r__))
    return right_ascension, declination