(a) No person may operate an ultralight vehicle except between the
hours of sunrise and sunset.
(b) Notwithstanding paragraph (a) of this section, ultralight vehicles
may be operated during the twilight periods 30 minutes before official
sunrise and 30 minutes after official sunset or, in Alaska, during the
period of civil twilight as defined in the Air Almanac, if:
(1) The vehicle is equipped with an operating anticollision light
visible for at least 3 statute miles; and
(2) All operations are conducted in uncontrolled airspace.