def sidereal_time(t):
    """Compute Greenwich sidereal time at the given ``Time``."""

    # Compute the Earth Rotation Angle.  Time argument is UT1.

    theta = earth_rotation_angle(t.ut1)

    # The equinox method.  See Circular 179, Section 2.6.2.
    # Precession-in-RA terms in mean sidereal time taken from third
    # reference, eq. (42), with coefficients in arcseconds.

    t = (t.tdb - T0) / 36525.0
    st =        ( 0.014506 +
        (((( -    0.0000000368   * t
             -    0.000029956  ) * t
             -    0.00000044   ) * t
             +    1.3915817    ) * t
             + 4612.156534     ) * t)

    # Form the Greenwich sidereal time.

    return (st / 54000.0 + theta * 24.0) % 24.0
Compute Greenwich sidereal time at the given ``Time``.