If you are one of the many people who enjoyed seeing and photographing Comet C/2022 E3 ZTF (“the Green Comet”) in late 2022/early 2023, or who wondered about Comet NEOWISE (pictured above), you’re probably wondering when you’ll be able to see another comet, and preferably a much brighter one.
Well, absolutely no promises, but towards the end of 2024 we may have a comet in the sky as bright as E3 was, or even brighter.
If the most optimistic predictions are to be believed, it may even be the best comet in a long time. There are even whispers that it is a large comet!
But calm down. It is far too early to make such predictions.
The ball of ice and dust that raises eyebrows and raises hopes is called C/2023 A3 (Tsuchinshan-ATLAS).
It was discovered in February 2023 during a sky survey by ATLAS – Asteroid Terrestrial-impact Last Alert System – using the 0.5-mf/2 Schmidt Reflector Telescope operated at the Sutherland Observatory in South Africa.
Back then it was just an uninspiring 18th size spot on a photo, and it was given the equally uninspiring name ‘A10SVYR’.
However, when its orbit was calculated, it was noted that it had already been detected by the Purple Mountain Observatory in China, on January 9, 2023, when it was at magnitude 18.7.
Follow-up observations revealed that A10SVYR had a short tail, so it was designated as a comet, and following the long-established naming convention, it was given a name honoring both of its discoverers: C/2023 A3 (Tsuchinshan–ATLAS).
Why is everyone talking about C/2023 A3 (Tsuchinshan-ATLAS)?
Crunching the numbers showed that Comet A3’s orbit will bring it close enough to both the Sun and Earth in September/October 2024.
There is a good chance that it will be visible to the naked eye, and has it potential to be a bright comet to the naked eye.
It’s easy to get carried away by this, but perhaps understandable. It’s been way too long since we had a really bright comet in the sky.
You may remember how beautiful comet Hale-Bopp was back in 1997, and even if you didn’t see it yourself, if you mention its name at an astronomical society meeting, you’ll see many of the people smiling as fond memories of seeing its twin tails painted on the spring sky come streaming back.
But anyone predicting the A3 will be ‘another Hale-Bopp’ is very unwise. It’s still way too early to know what it will do and how bright it will be.
What do we know about C/2023 A3 (Tsuchinshan-ATLAS)
Initial data suggest that comet C/2023 A3 completes one orbit every 80,000 years.
Comet C/2023 A3 is currently between the orbits of Jupiter and Saturn as of March 2023 and will reach perihelion – the closest point to the Sun in its orbit – on September 28, 2024.
We know that currently A3 is so faint that it is only visible in large telescopes, and this will not change for months.
We know that if it behaves itself, early summer 2024 it ought to beginning to become visible in the evening sky through small telescopes.
That power be bright enough to be visible through binoculars or even with the naked eye in late September 2024, when it will be a pre-dawn object, much low in the east before sunrise.
Will it have a tail by then? We do not know. It all depends on how old and how active the comet is, and experts are still figuring that out.
We will lose sight of the comet in early October 2024, when it passes very close to the Sun as seen from Earth.
Some people wonder if A3 will be visible during the day by blocking the Sun, but they wondered the same thing about Comet ISON a few years ago and it never happened, so let’s not even go there now.
If the comet survives its passage around the Sun, the main northern viewing period will begin after October 11 or 12, 2024, when the comet will move up into the evening sky, visible after sunrise, slightly higher and easier to see each evening.
How bright will the C/2023 A3 be?
How bright will the comet be in mid-October?
Some experts suggest that it may reach first or even zero magnitude, making it obvious to the naked eye (for information on what this means, read our guide to stellar magnitudes)
Others say we’ll be lucky if it’s even third, which would make it “another E3” not “another Hale-Bopp”, only visible to most people through binoculars. We just don’t know.
If this all sounds very vague, that’s just the way it is. Comets are difficult to predict and have a habit of not living up to expectations.
The comet is far, far away, and not doing much yet.
But as it gets closer and more and more people see and photograph it, we’ll have a better idea of what it will do as it approaches and then passes us in late 2024.
Keep checking back on this page. We will keep you updated!
Find out more about the comet via the International Astronomical Union’s Minor Planet Center or at astro.vanbuitenen.nl/comet/2023A3.