A rare celestial sight lit up Edmonton’s night sky Friday.

Friday night’s full moon was called a Triskaideka-Micro-Harvest Moon.

It’s a Harvest Moon, because it’s the closest full moon to the autumn equinox, and it’s the first time one has been seen on Friday the 13th.

Triskadeika is the Greek word for 13.

Friday’s moon is also a Micro Moon. That’s when the moon appears smaller because the full moon occurs when the moon is at the furthest point in its orbit around the earth (known as the apogee). This is the opposite of a Super Moon.

The last Friday the 13th full moon was in October of 2000, but that was a Hunter’s Moon, not a Harvest.

This makes last night’s moon, a once-in-a-lifetime sighting.