In Canada, can an ultralight be flown at night or IFR by a PPL pilot with a night flying or IFR endorsement if the ultralight is equipped for night flying or IFR ( eg. heated pitot tube, nav lights, etc.) and a seatbelt?
In the US, per 14 CFR Part 103.11, you can not operate an ultralight at night or IFR. You can, however, register it as an aircraft. Which, at that point,it no longer qualifies as an ultralight.
§103.11 Daylight operations.
(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.
Just found the following ( Source: Challenger.ca ): Aircraft registered as Ultralights may only be operated in Day VFR conditions. You can operate a Challenger at night or under Instrument Flight Rules if it is registered in the Aeroplane category as an Amateur-Built and if it complies with the lighting, instrumentation and other equipment requirements.