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Rare 19-year ‘blue moon’ may beam down on Halloween Night in Prince George

Coincidental lunar orbit adds to 'craziness' of 2020, says one local astronomer
Blue full moon - Getty Images
A rare full blue moon is set to illuminate the Prince George sky on Halloween 2020, an event that occurrs once every 19 years. (via Getty Images)

The year 2020 has arguably best fitted the phrase ‘once in a blue moon’ when it comes to a variety of circumstances, events and down-right surprises.

Halloween this year will be no different as a rare ‘full blue moon’ is set to illuminate the northern sky Saturday night (Oct. 31) while residents will be practicing COVID-safe trick-or-treating.

Now, the moon itself won’t be the literal colour blue.

Prince George Astronomical Society spokesperson Blair Stunder explains it’s going to be slightly brighter because it will have appeared twice in the same month.

“The lunar cycle is approximately 29.5 days from full moon to full moon,” he tells PrinceGeorgeMatters.

“A lunar orbit is slightly elliptical, putting the moon about 358,000 km from Earth with a 50,000 km variance, which really to the naked eye, makes it slightly brighter. Light follows the inverse square rule and if you double the distance, you have double the illumination.”

What also makes this occurrence so unique, fittingly so with 2020, is that the ‘blue moon’ falls on Halloween once every 19 years.

This pattern is known as the Metonic Cycle, which Stunder says is the alignment of the moon’s lunar orbit with Earth’s adjacent orbit with the sun.

“It’s just a matter of where the Earth is going to be located in the solar system going around the sun, so the moon is [basically] going to be in the same spot. If you use a telescope, you’ll want to look at the edge of the moon because there’ll be a star at the edge of the moon.”

Coincidentally, in adding to the madness, daylight savings time in B.C. will also end on Halloween night, providing an extra witching hour for residents to haunt, trick and enjoy the sight.

But watch out for werewolves and monsters lurking in the shadows, a joke not entirely intended, as Stunder says a bright blue moon tends to mess with human emotions.

“The extra gravitational pull makes people act funny. Gravitational pull has an effect on the moon and so the strength of light we’re going to get may cause heightened senses or ‘crazy’ reactions, in a manner of speaking.”

Stunder explains, so long as the weather holds up with few clouds in the evening on Saturday, the ‘blue moon’ will peak as early as 8:30 p.m. in Prince George and will be high enough in the sky for viewing until 4 a.m. (Nov. 1).

He adds the best vantage point is an open area with little surrounded lighting, such as homes and street lights.

According to the Old Farmer’s Almanac, the next illuminated Halloween full moon before the next century will be in 2039, 2058, 2077 and 2096.