Moon dogs over Winnipeg, Manitoba
© Scott McCulloughMoon dogs appeared in the Manitoba sky early Thursday morning.
Winnipeggers were treated to a relatively rare sight in the inky sky early Thursday before sunrise.

Bright spots, known as moon dogs, were visible on both sides of a halo that ringed the moon.

The lunar halo and spots only happen when there are ice crystals in the air and the moon is bright enough - quarter moon or more - to shine light that can be refracted by the crystals, according to The Stargazer's Guide to the Night Sky.

The moon was full just one night earlier. In fact, it was a supermoon, which happens when the moon is full at the same time it is the closest distance in its orbit to Earth.

Moon dogs are like sun dogs but rarer. Sun dogs simply need the crystals in the air.

And on Thursday, when the sky brightened, making the moon's glow dim, the sun dogs came out.

Thursday's phenomenon comes one day after another extremely uncommon occurrence - a super blood blue moon.

It was the first alignment of a blue moon (the second full moon in a calendar month), a total lunar eclipse and a supermoon since 1866. The blood part of the name comes from the eclipse, known as a blood moon for its red tint.

The next supermoon can be seen in February, the next blue moon is in March and the next total lunar eclipse is in July.

But the combination won't happen again until 2037.