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A passing comet could shine as bright as Venus. Here are the best viewing times

The comet Neowise appears in the night sky above Vancouver, on Monday, July 20, 2020. (Darryl Dyck/The Canadian Press) The comet Neowise appears in the night sky above Vancouver, on Monday, July 20, 2020. (Darryl Dyck/The Canadian Press)
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An eye-catching celestial event is around the corner. Comet C/2023 A3, known as the Tsuchinshan-ATLAS, will make an appearance in the skies this fall.

The newly discovered comet is projected to pass near the Earth, offering stargazers a chance to see a comet that has travelled millions of years in orbit to reach us.

Here is how you can observe the comet:

When and where to see Comet C/2023 A3

The comet could shine as brightly as the planet Venus in the coming weeks and give Canadian viewers a fair shot at spotting the comet, according to Paul Delaney, a professor emeritus of Physics and Astronomy at York University.

“In and around October 15,16, 17, where in evening twilight, so when the sun has set and the sky is getting somewhat darker, that’s going to be our first opportunity to see it, if it is, in fact this bright,” Delaney said in an interview with CTVNews.ca Monday.

“As October stretches on, it will get more visible in darker skies,” he said, while adding that the further away from the sun, the comet’s brightness is expected to drop.

For those on the southern hemisphere, including those living in countries like Australia and New Zealand, Delaney said the comet was a little further out and therefore fainter.

Delaney said September 11 or 12 was when visibility peaked for those south of the equator and because it will swing in and get closer to the sun at the end of September, they are not well placed for looking at this comet.

About C/2023 A3

Comets like C/2023 A3 are “big, dusty ice balls,” and when they start coming in close to the sun, they heat up and begin to discharge gasses and dust and that’s what create comet tails, Delaney said.

But he warned that comets are mostly “unpredictable” and this would be “the first time we’ve seen this comet.”

While some astronomers claim this will be the brightest comet in recent years, even calling it the “comet of the century,” Delaney warned that such claims have been made about previous comets that haven’t lived up to expectations.

According to Delaney, the comet originated from the Oort cloud and has taken millions of years to get to us here.

In response to concerns of the comet’s disintegration, Delaney said “if it was going to fall apart, it probably would have done it by now,” adding that it’s still a possibility.

Comets that get close to the sun get broken up because of tidal forces and if it’s not solid. “We don’t know its characteristics, it could well be pulled apart by the gravitational forces of the sun as it swings through perihelion at the end of September.”

Delaney said they are still trying to assess whether it’s next move will be to return to the Oort cloud or escape the solar system after its visit to the northern hemisphere.

“The closer we get to the middle of October, we will be able to predict with increasing certainty how bright this [comet] will be, assuming it survives passage wit the sun and perihelion,” Delaney said.

Tips for stargazing

For the best experience of the comet, stargazers should ensure a clear, unobstructed view and choose a location away from city lights.

“The darker the sky you can observe from the better,” Delaney advised. “If you can drive half an hour outside of the city to a friend’s place that’s darker that will improve the quality of the view.”

“If our predictions are in fact correct, even city lights are not going to dim [the comet],” Delaney said.

He said that it will be harder to see the comet’s tail the brighter light pollution is, and if you’re stuck in the city, find the darkest spot in your backyard or local park.

While the comet may be visible to the naked eye, a pair of binoculars or a small telescope will help enhance the view. 

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