Caoimhín's Content

Today we are going to be taking a look at a few comets. The comets that we’re going to be taking a look at are rather newly discovered, I had to add them to Stellarium. I’ve gone into greater detail about that process before, but I will briefly outline it again, for the second comet.

The first comet that I want to take a look at is around the constellation Aquila, though it may have moved into Delphinus by now. This means we want to be looking roughly in the direction of the Summer Triangle, and given that we are very much into winter, the summer triangle’s coming up in the morning. Looking at the sky reasonably early, about 6:20 in the morning, and the summer triangle is nice and clear over to the east, and it is completely up, all of the summer triangle is visible.

We’re looking for a comet that was discovered in 2026, so it may not already exist in Stellarium, but that’s okay as we will be able to add it to the software. It doesn’t come up when searched for normally, that’s the sign that we’re going to have to add the comet into Stellarium. That means using the Solar System editor, which is a plugin that needs to be running when Stellarium starts up. The Plugin tab of the configuration window is where you will find it to turn it on, and once you restart the editor will be visible as a button in the Solar System Objects tab of the Sky and Viewing Options window. I’ll explain the adding process shortly. The first comet is C/2026 B2 Sun-Gao. It was discovered by two astronomers in China, Guoyou Sun and Xing Gao. With that added to the Stellarium software we can find it through the normal search. By mid-February it is after moving out of Aquila and into Delphinus, so it hasn’t moved that far. We’re seeing this comet as pretty faint at the moment, it’s only magnitude 12. This comet had its closest approach to the Earth already a little bit earlier in January. If we zoom in a bit, it’s just about showing up, and it has a little bit of fuzzy coma around it even though we’re not quite getting a tail. The lack of tal does make sense.

The comet is already further from the Sun than we are and also pretty far from us, so on the far side of the Sun. Moving back in time, it does get closer to us and closer to the Sun, but the closest it gets to us is still 2.029 AU away a little bit further back in January. It is still visible to us, through telescopes, at magnitude 12. Taking a look at its closest approach to the Sun, that was reached a little bit earlier in January, and the comet was still around an AU away from the Sun. The closest position to the Sun is when the comet is going to be at its brightest, and it was still only magnitude magnitude 12. This comet is newly discovered, as you can tell from its name. It’s C/2026 for this year, and B2 for the second discovery in the second half of january. It is a periodical comet, but the orbital period is roughly 233 years, so this comet is going to take a very long time to orbit the Sun. As we can tell from its distances, this is a comet that doesn’t get as close to the Sun as we do, but based on its period, it must get very, very far away from the Sun.

This comet was discovered in January 2026, but by reviewing images of this region of the sky, it was found that we actually got pictures of this comet in 2025, back in December. This is a phenomenon that often happens with comets called precovery. The comet is officially discovered when it’s recognized to be a comet, identified to be a comet, but by reviewing images of the same region of the sky astronomers can often find evidence of the comet before it was officially discovered, and that’s precovery. Occasionally precovery can be a year or even more before the official discovery, but it’s usually a little bit shorter, usually only a few months. We’re going to take a look for another comet now that was also discovered in 2026, right at the start of 2026, C/2026 A1 MAPS. As we can tell from the A1, this was the first comet discovered in the first half of January, so the first official discovery this year. It looks like this comet also isn’t already included in Stellarium, but that’s okay, we will go through the same process and add it via the Solar System Editor. Using the Solar System tab of the editor, we can import orbital elements in MPC format, which requires an internet connection. Using the online search, presuming the name is spelled correctly, the object will appear and can be selected and added to the software.

The discoverer here is listed as MAPS, but MAPS is actually a program ran as part of an observatory in the Atacama Desert. Rather than being an individual telescope, it is a program that uses the Atacama Large Millimeter/submillimeter Array or ALMA to the detect Molecules at PLanet Forming Scales (MAPS). Occasionally these comets are named after the people who discovered them, occasionally they’re named after the observatory or the automated system that has discovered them. This comet is above the horizon after sunset, just a little bit under Orion. Currently it is very faint, just 18th magnitude, but this comet is going to continue getting closer to us and closer to the Sun as we move forward. It just reaches its minimum in April, it’s closest to us is just under an AU away, but it is significantly closer to the Sun. This proximity to the Sun really increases its magnitude. It’s a bit too close to the Sun for us to easily see, but it gets up to sixth magnitude while still visibly to the side of the Sun. It gets up to magnitude 1 and beyond when it’s right behind, or right in front of, the Sun. Right next to the Sun is a very difficult position for observation, and that happens in April.

This comet is going to take a while before it gets close to us, and when it is at its closest to us, there’s a good chance that it won’t be visible from here in Ireland. Even if we get rid of the trees and bushes that are in the way so that we have a perfectly flat horizon, the Sun still isn’t going down very long before the comet, mostly thanks to the angle. If we head down to the equator, or at least close enough to the equator, we should get a better view. To make sure it isn’t too close to the Sun, we need to move away from its perihelion and brightest point. It might not quite visible to the eye even at magnitude 7, as there will be too much sunlight in the sky for it to really be visible. This comet should be visible through telescopes from the Northern Hemisphere once we’re a little bit further into the future, but thanks to its discovery in January we have plenty of time to prepare.

Taking a closer look, there is definitely a coma around this comet and it gets very close to the Sun, so I’d expect in reality that this comet would have a tail when it’s in this position, even though Stellarium isn’t showing it. This comet has an incredibly long period, 1175 years. This is a very long period for a comet to have, and it is getting very close to the Sun. Once it reaches its minimum distance to the Sun, Stellarium shows the distance in kilometers rather than in millions of kilometers. It is many kilometers, but that’s still very close for a cometabout 0.0125 AU from the Sun. Getting rid of our atmosphere lets us follow the comet during its perihelion a bit easier. Just about when it’s at its closest to the Sun it reaches a peak brightness of -7. That’s incredibly bright, but of course it’s happening during the day. Even with that incredible, incredible level of brightness, we’re not quite going to catch it.

This comet is visible at sunset on either side of its closest approach. Continuing to move forward, we would expect the comet to emerge on the other side of the Sun, bringing it up in the morning time rather than the evening time. Just at sunset, with absolutely no atmosphere, it’s just about visible to the naked eye. With the light of the Sun, it is unfortunately blocked out, even at magnitude 6 or 7, making it a tricky one to catch. Looking at the sky from very near the equator in as we come into northern summer, we are looking ahead into April, everything feels a little bit odd to me because the Sun is practically arcing across the northern sky. As we move through time, the comet moves in towards the Sun, vanishes, and then pops back up. It looks like this comet is not moving around the Sun in the way I’d expect. It makes an approach to the Sun, it swings around the Sun and then comes back out again, essentially the way it came from our perspective. This implies to me that this comet has a very tight orbit, that it is very elliptical. That would make sense with its incredibly long period, over a thousand years.

That comet is going to be much more visible in the first future when it’s closer to the Sun, but thanks to the angles at which we’re going to see it, it is going to be very difficult for us to see here in Ireland. Coming back to February, it’s nice and high above the horizon down next to the equator, but moving all the way back up to our latitude puts it much closer to the horizon. They are a couple of comets that were just discovered this year, right in January. They’re either just after making their closest approach or will be coming up to their closest approach once we get into April. C/2026 B2 Sun-Gao is best caught soon, while C/2026 A1 MAPS is very much one to look forward to. I hope you get to see those comets, presumably with a telescope. If you don’t get to see those comets in real life, at least you’ve gotten an idea of what they will be like here. I hope that you enjoyed this piece, if you did then please do like it and please subscribe to this website and my YouTube channel. Thank you very much for reading and hopefully I’ll see you back here next time.