When and where in Canada to get the best view of Saturday‘s ‘blood Moon‘

Early risers across Western and central Canada this Saturday, April 4, will get treated to a ‘blood Moon’ as Earth’s companion undergoes the briefest total eclipse this century.

Lunar eclipses occur whenever the Sun, Earth, and the Moon line up such that our planet’s shadow is cast onto the lunar disk. Over the course of about an hour or so, the shadow appears to slowly creep across the the moon, taking bigger and bigger bites until the entire silvery orb has dramatically darkened.

When the moon enters the darkest part of Earth’s shadow the lunar disk can turn a coppery-red colour known as the totality phase of the eclipse. This dramatic reddish hue occurs because sunlight has passed through Earth’s atmosphere, which filters out most of its blue light and this refracted light then is cast on the lunar surface, earning the nickname ‘blood Moon’.

While Canadians west of the Ontario-Manitoba line will get to see most of the eclipse, skywatchers in Eastern and Atlantic Canada will only get to enjoy parts of the first half of the cosmic event in the predawn sky. That’s because by the time totality begins, the moon will be setting fast in the west just as the sun is rising in the east.

The sky show begins at 3:15 am Pacific Daylight Time (6:15 am EDT) this Saturday morning, when the first hints of the partial eclipse begins. Then at 4:58 am PDT the Moon will become totally eclipsed as it enters the deepest part of Earth’s shadow, dubbed the umbra.

Making this lunar eclipse a bit more noteworthy is that totality will last only a mere four and half minutes long, much shorter than the average blood moon, which can last upwards of an hour. According to NASA astronomers this brevity is caused by the moon only skirting the outer edge of the dark umbra shadow, making this the shortest of all eclipses occurring over the course of the entire 21st century.

The height of the eclipse will be at 5:01 am PDT, by which time the moon will have set for sky-watchers east of Manitoba. Eclipse watchers on the West Coast, northwestern British Columbia and the Yukon will have front row seats for the entire show, able to see even the very last little bit of Earth’s shadow leave the lunar disk at 6:44 am PDT.

While the Moon does reach full phase every month, it is a rarer occurrence for it to be covered by Earth’s shadow and change colour.

Since the Moon’s orbit is tilted with respect to Earth’s orbit around the Sun, the Moon does not cut through Earth’s shadow cone every month.

Exactly what colour the Moon will turn during totality cannot be predicted; it changes from eclipse to eclipse. The more the dust particles in Earth’s atmosphere at the time of the eclipse, the darker shade of red the moon can appear. For instance, large volcanic eruptions pump ash particles into the upper atmosphere that can scatter sunlight, shifting toward the red part of the spectrum.

But with the unpredictable weather this time of year there is a chance that you might get clouded out. Even If you happen to be stuck indoors, though, you can still check out the lunar disappearing act thanks to a live online broadcast by astronomy outreach venture The Virtual Telescope Project. As part of Global Astronomy Month, the biggest worldwide celebration of the cosmos, telescopes will be webcasting the entire lunar eclipse from multiple sites around the world.

And if you do miss this one, it turns out this will be the third in a series of four lunar eclipses spaced out every six months or so, known as a tetrad — with the fourth and last one occurring on September 27, 2015. This cosmic tetrad is indeed a rarity that won’t repeat until the year 2032.