def hour_angle_deg(true_solar_time):
    """Returns Hour Angle in Degrees, with True Solar Time, true_solar_time."""
    if true_solar_time / 4 < 0:
        hour_angle_deg = true_solar_time / 4 + 180
    else:
        hour_angle_deg = true_solar_time / 4 - 180
    return hour_angle_deg
