{"id":2892,"date":"2023-03-04T12:10:37","date_gmt":"2023-03-04T12:10:37","guid":{"rendered":"https:\/\/www.popastro.com\/main_spa1\/comet\/?p=2892"},"modified":"2023-03-04T12:10:37","modified_gmt":"2023-03-04T12:10:37","slug":"a-great-comet-for-2024","status":"publish","type":"post","link":"https:\/\/www.popastro.com\/comet\/2023\/03\/04\/a-great-comet-for-2024\/","title":{"rendered":"A Great Comet for 2024?"},"content":{"rendered":"

It\u2019s been a long time since a really bright comet appeared in the sky. A couple of years ago Comet NEOWISE was a delight, and many people were thrilled by the sight of its curved tail shining in the sky close to the Big Dipper after sunset. More recently \u201cthe Green Comet\u201d, Comet C\/2022 E3 ZTF was visible to eagle-eyed observers blessed with dark sky locations well away from light pollution, and was a lovely sight for everyone else who saw it through binoculars and small telescopes.<\/p>\n

But the last Great Comet \u2013 a comet that was very obvious to the naked eye to everyone, regardless of their knowledge of the sky (note: that\u2019s my definition, not an official one!) \u2013 was probably peacock-tailed Comet McNaught, which was a wonderful sight in 2007, at least for southern hemisphere observers. Before then? Well, Hale-Bopp is the comet everyone remembers, of course. That comet was a spectacular sight in 1997, and if you even just say its name to a generation of amateur astronomers they will smile wistfully, instantly transported back to that wonderful Spring when Hale-Bopp\u2019s twin tails were sprayed across the sky and the comet seemed reluctant to leave our sky, shining in it for what seemed like an age, being photographed with SLR cameras fitted with 400ASA slide film, in ye olden days before digital SLRs, 1Gb memory cards and ISOs of tens of thousands…<\/p>\n

Yes, it\u2019s been a long time since we had something like that to observe and photograph. But the long wait might be over. Possibly. Perhaps. Maybe.<\/p>\n

Last week comet observers felt a strange disturbance in the Force as whispers began to spread across social media that an object discovered during one of the many automated sky surveys might be something\u2026 interesting. During a sky search performed by ATLAS \u2013 the Asteroid Terrestrial-impact Last Alert System<\/a> – using the 0.5-m f\/2 Schmidt reflector at the Sutherland Observatory in South Africa, an object with an estimated magnitude of 18.1 was detected in images taken on 22 February 2023. At that time the object \u2013 labelled \u201cA10SVYR\u201d – was around 7.3 AU (1.09 billion km; 680 million mi) from the Sun. After the object\u2019s orbit was calculated it was noticed that it was the same object reported to the Minor Planet Center by the Purple Mountain Observatory in China, which had detected it earlier, in images taken on 9 January 2023 when it was magnitude 18.7. It was reported then but when no further observations were made or reported it was considered lost \u2013 until the ATLAS survey found it again. Subsequent observations revealed the object had a short tail, so it was designated a comet.<\/p>\n

Based on the long-established naming convection for comets A10SVYR was given a name honouring both observatories, and is now known as comet C\/2023 A3 (Tsuchinshan\u2013ATLAS).<\/p>\n

Discoveries like this happen daily now, and make barely a ripple in the astronomical world. Fire up your favourite astronomy phone app and ask it to show you which comets are visible in the sky and your screen will absolutely fill with them, so many they almost cover the stars. So why is this comet \u2013 which I\u2019m going to call \u201cT-ATLAS\u201d from now on because I\u2019m not typing that full name out every time! \u2013 raising both hopes and eyebrows? Because when multiple observations were collected, and the numbers were crunched to calculate its orbit, it became clear that T-ATLAS had the potential to become visible to the naked eye late in 2024, and perhaps even very<\/em> bright.<\/p>\n

Could T-ATLAS be a Great<\/em> <\/strong>Comet? Is another Hale-Bopp on its way? No. At least, that\u2019s very unlikely. For a start, T-ATLAS will not be visible high in a dark sky, like Hale-Bopp was, and it will only be in the sky for a short time when it is at its brightest too. But if it behaves itself, and doesn\u2019t spring any nasty surprises, then T-ATLAS might be easily visible to the naked eye next September and October.<\/p>\n

Inevitably \u2013 and perhaps forgiveably, given how long it has been since we had a properly bright comet in the sky – there is a lot of speculation and uninformed commentary about T-ATLAS. The numbers suggest that it could reach a negative magnitude at its maximum, but we just don’t know, and it will be very close to the Sun in the sky at that point anyway. Either side of that it might<\/em> reach first or even zero magnitude. Renowned and trusted comet expert Gideon van Buiten has estimated that the comet will reach a magnitude of 0.9 during perihelion and -0.2 at the time of the closest approach to Earth, but others are suggesting the comet\u2019s peak brightness will be only 3 or even 4. More than a year and a half away from when the comet begins its show it\u2019s best to take any predictions with a pinch of salt.<\/p>\n

While it\u2019s important to not over-hype comets like this when they are found, it\u2019s also important to not go too far the other way and dismiss the possibility of them becoming something special; putting people off looking for comets is just as bad as firing them up with over-optimistic expectations. In the months ahead this comet is going to be observed and studied relentlessly, and as our understanding of its orbit, size and development grow we will be able to make more accurate and realistic predictions about what it MIGHT do next September and October. For now, all we can say with any confidence is that T-ATLAS is on its way, and should be visible to the naked eye late next year, and might\u2026possibly<\/em>\u2026be a bright naked eye comet.<\/p>\n

It\u2019s a clich\u00e9, I know, but we really will just have to wait and see.<\/p>\n

In the meantime, where is it? Astronomy apps like Sky Safari and planetarium programs like Stellarium now have this new comet \u00a0in their solar system objects databases, so I\u2019ve made some charts which show where it is now and where it will be in the future. It\u2019s VERY important to note that these are just intended to show very roughly where and when the comet will be visible in the sky \u2013 the northern sky only, for now, I\u2019m working on southern hemisphere ones, be patient! – and have been made using the info available on Stellarium now, which will change as more observations come in and the comet\u2019s orbit is refined. They are drawn for UK latitudes, for the times and dates stated on each chart.<\/p>\n

Note: please<\/em> ignore the “look” of the actual comet – this is just how Stellarium draws comets, and these charts should not be taken as predictions of tail lengths. We have absolutely no way of knowing that at the moment, and won\u2019t even know that until the tail appears, if it even grows one.<\/p>\n

So what DO we know?<\/p>\n

Long story cut short? For northern observers the best times to look will probably be…<\/p>\n

Morning sky, before sunrise: Sept 27 – Oct 7<\/p>\n

Evening sky, after sunset: Oct 13 – 20<\/p>\n

The comet will pass very close to the Sun in the sky between Oct 7 and 11.<\/p>\n

Now, the obvious question is HOW BRIGHT WILL IT BE???? \u00a0As I said earlier there’s already a lot of speculation about this comet online, some very informed, some not so much, but it’s way too early to be making confident predictions about that. There are many comet observers who will be able to provide excellent advice and information about that as this develops, and I\u2019ll pass on their work. Listen to them over the months ahead, and not the hype that is inevitably going to surround this comet.<\/p>\n

For now, for the morning sky Stellarium is giving a magnitude of 1.0 on Sept 27th, increasing to 0.6 by Oct 7th. For the evening sky Stellarium is giving a magnitude of 1.1 on Oct 13, and 2.5 by Oct 20th. ** Do NOT take these as accurate predictions! **<\/p>\n

\u2026and there you have it. Bottom line? In a year and a half we might<\/em> have something special in the sky \u2013 or we might not. It\u2019s just far, far too early to say with any confidence, and comets do love to frustrate and disappoint us. So when you start reading breathless online pieces about a \u201cmega comet\u201d that will \u201cblaze in the sky\u201d next year just smile and move on.<\/p>\n

But as sensible as it is to be cautious, it\u2019s important not to pour too much cold water on this comet\u2019s potential this early too; we don\u2019t want to burst its balloon, and deflate the hopes of those looking forward to seeing it. All the numbers suggest T-ATLAS is very promising, so let\u2019s celebrate the discovery of this new comet and embrace the possibility that it might be a real treat late next year.<\/p>\n

Keep checking back for updates on this new comet!<\/p>\n

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It\u2019s been a long time since a really bright comet appeared in the sky. A couple of years ago Comet NEOWISE was a delight, and many people were thrilled by the sight of its curved tail shining in the skyRead more<\/span><\/a><\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[9],"tags":[],"class_list":["post-2892","post","type-post","status-publish","format-standard","hentry","category-comet-news"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t