The forecast calls for a chance of clouds Thursday night, but with any luck, a Blood Moon will be visible to Island sky-watchers during a lunar eclipse.
The term Blood Moon comes from the distinct red colour the moon will turn during the eclipse, said Randy Enkin, past-president of the Victoria chapter of the Royal Astronomical Society of Canada.
He said the colour results from a set of conditions that happen only two or three times a year.
“The moon travels through the Earth’s shadow, so there’s a perfect alignment of the sun, the Earth and the moon,” Enkin said. “The Earth always casts a shadow, but usually the moon goes above it or below it.”
In this case, some of the moon’s light in the red spectrum will make it through the Earth’s atmosphere without being scattered, he said.
“That is the light that goes onto the moon and makes it look red,” Enkin said. “It’s a wonderful thing that people have been keen to observe since many thousands of years ago.”
The full eclipse will be from about 11:30 p.m. Thursday to about 12:30 a.m. Friday, and the whole event will be over by about 3 a.m. Friday.
Lunar events like Thursday night’s are also referred to as a Blood Worm Moon or just Worm Moon — a reference to the American Farmers Almanac calling a full moon in March a Worm Moon because it happens around the time that worms tend to emerge from the ground.
Enkin plans to host his own eclipse party Thursday evening, while a sold-out event is being held at the Dominion Astrophysical Observatory.
“My feeling is that all the full moons are beautiful, whether it is the Harvest Moon or the Worm Moon,” he said, noting the W̱SÁNEĆ name for the moon between mid-February and mid-March is WEXWS — the Moon of the Frog.
Lunar eclipses played a role with some ancient populations, helping them realize the earth is round, he said.
“They understood what the eclipse was,” he said. “There was no question of the Earth being flat. They saw the shape of the shadow and they said that is telling us the Earth is a ball.”
Expect Thursday’s spectacle to start about 9 p.m., with Earth’s shadow likely to be visible moving across the disc of the moon by about 10 p.m., Enkin said.
The curvature of the Earth will be visible from our vantage point about 400,000 kilometres away from the moon, he said.
“It gets really exciting in that time from 10:30 to 11 o’clock — that’s my favourite time.”
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