How to view Comet C/2023 A3 in Brisbane this week
Queensland is set to have front row seats for the best comet in more than 10 years. Where it can be seen from and the times you can see it explained.
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Queensland is set to have front row seats for the best comet to be seen in more than a decade.
University of Southern Queensland astrophysics professor Jonti Horner said the “best comet of the year” C/2023 A3 (Tsuchinshan – ATLAS) will be able to be seen in bare eyes.
What is a comet?
Prof Horner said a comet is an object made of ice, rock and possibly rid of metals, which is often described as a “dirty snowball”.
“When they fall towards the sun, when they get closer to the sun, they get hotter, and on their surface, when it gets hot enough that the ices can no longer be ices, they turn into gas,” he said.
“They don’t become a liquid, because there’s no atmosphere.
“That gas and dust, that’s now in space, encounters the influence of the sun.
“The sun blows what we called the solar wind, a really fast wind blowing at more than 100km/s.
“It also gives off lots of radiation, and those two things combined push the gas and dust away from the sun, and that’s what gives you the comet’s trails.”
He added people cannot actually see the snowball in the middle unless using a big telescope as it will be hidden in gas, but the coma and the tail will both be visible.
When will the comet be most visible?
For Brisbane, Prof Horner said the comet set will be at 6.30pm on Saturday, 6.50pm on Sunday, 7.05pm on Monday and 7.20pm on Tuesday.
For Cairns, he said the comet set will set about 7pm on Saturday, 7.15pm on Sunday, 7.35pm on Monday and 7.50 on Tuesday.
He said people will start seeing it on Saturday and more until Wednesday next week when it will be higher in the sky.
He recommended people go out 30 minutes to 45 minutes after sunset.
Where to watch?
Prof Horner said there will be a slight difference as people further north enjoy a better view.
But he recommended people to go away from the bright city lights to a place with no trees, buildings or hills for a low horizon and to look west when the sky is getting darker, including Darling Downs South West near Toowoomba.
How often can I see a comet with my naked eyes?
Prof Horner said there are three things affecting the brightness of a comet, and the majority of them are too faint to be seen. He said a bright one that is very easily seen in the naked eyes comes once every 10 years on average.
“A smaller comet will make less gas and dust than a bigger comet,” he said.
“A comet that comes closer to the sun will get hotter and therefore become more active and give off more gas and dust.
“The closer the comet is to the earth, the brighter it will look.”
Prof Horner said Queensland has not had a spectacular comet in the sky since 2007 despite debates about the 2011 one.
Where did the C/2023 A3 (Tsuchinshan – ATLAS) come from?
It is a comet, discovered in 2023 by China’s Purple Mountain Observatory and Asteroid Terrestrial-impact Last Alert System with a very long orbital period. It is a fragment left behind when the planet was formed 4500 million years ago. It spent almost that time in the Oort cloud.
Prof Horner said it is the very first time for the earth to see it and probably the last time to view it as well as it might not return to the solar system.
How can I find C/2023 A3 (Tsuchinshan – ATLAS)?
The comet will be on the right side below Venus, which looks like an aircraft with its headlights on.
What is the weather forecast?
The Bureau of Meteorology estimated the east coast to be cloudy, with a shower or two for the upcoming seven days, but the inner west Queensland was set to be clear and mostly sunny.
Prof Horner said people will be able to see the best comet of the year as long as the skies are clear.
Originally published as How to view Comet C/2023 A3 in Brisbane this week
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