Calgarians can prepare to witness a total solar eclipse on April 8

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On April 8, Canada will experience a majestic celestial event last witnessed in the country 45 years ago — a total solar eclipse. Locally, anyone interested in catching a glimpse of this once-in-a-lifetime occurrence will be able to do so at the University of Calgary’s Rothney Astrophysical Observatory.

Associate professor of physics and astronomy at the U of C, Dr. Phil Langill, explained it as the moon sitting in front of the sun and taking a giant bite out of it.

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“We live on a giant spinning ball, and we orbit in the sun, and the moon spins around the earth — and on April 8, there’s going to be a fantastic alignment between the earth and the moon and the sun, and the people in Calgary,” he said.

According to Langill, the eclipse will last for a couple of hours, and the part where the moon will be covering the sun is only going to last for approximately 20 minutes.

“This alignment between the earth, the moon, and the sun happens about every six months, so it’s not particularly rare from that point of view, but what’s rare is that the shadow of the moon is reaching down and touching the surface of the earth.”

Totality is going to happen all the way from northern Mexico through diagonally across the United States, coming out by the Great Lakes and hitting Canada in the deep southeast of Ontario and in southern Quebec and then heading off into the Maritimes, Newfoundland and Labrador.

“In terms of how many people are going to get a chance to see totality — it’s hitting every major city right across North America — it’s going to be pretty fantastic,” said Langill.

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‘Think about the motion of the universe’

The RAO will be set up on the main campus at Crowchild Trail on 32nd Avenue, right by the CTrain station with telescopes and eclipse-viewing glasses. It will host a panel of experts to talk about the eclipse and explain what’s going on.

Langill said the cool thing about the eclipse is that it is a reminder that we live in a dynamic universe. “During the eclipse, the sun and the moon are going to go across the sky from east to west, and that motion happens because the earth is a giant spinning ball,” he said.

“And that spinning action makes things rise and set.”

We get to watch the moon moving in its orbit because it’s going to take a bite out of the sun on the right-hand side, Langill said, and then it’s going to be right in the middle of the sun for a while.

“So this is a great thing because if you think about it, the universe is moving and we don’t normally think about that,” Langill said. “So if you can get people to think about the motion of the universe while the eclipse is going on, that’s really important.”

Safety paramount when observing an eclipse

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Dr. Phil Hooper of the Canadian Ophthalmological Society stressed the importance of safety when observing an eclipse and said people need to use special-purpose solar viewing glasses compliant with ISO 12312-2 standards.

“The biggest concern during any eclipse is that during the period that the moon is obscuring part of the sun, the sun isn’t as bright, and so it allows you to look at it without initially experiencing the discomfort you normally would,” Hooper said. As a result, there can be significant amounts of solar radiation entering the eyes — much more than what the eye can tolerate.

The biggest risk is during the period when part of the sun is visible, and that’s the part that people are most drawn to.

“It’s too much light energy being applied to the eye, and structures at risk include the front of the eye — although typically that is a relatively mild situation, giving you pain for a few hours — but the big concern is damage to the retina,” he said.

Because of the concentrated lighting, the temperature of the retinal cells can get above boiling point, and you can actually boil and damage the retinal cells, Hooper said.

“It’s much like taking a magnifying glass in the sun and focusing it on a piece of paper — if you have enough energy, it will actually cause the paper to burn,” Hooper said. “Similarly, in your eye, it’s focusing this light on a very small part of the retina, in a way that you’re not aware of, and it could do damage.

“It happens every time there is an eclipse — people don’t take precautions and have their eyes damaged.”

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