Comet C/2019 Y4 ATLAS

Comets, especially ones astronomers have not yet observed to visit the inner solar system previously, are notoriously fickle creatures. Comets of this type that also show some promise to be particularly bright and visible from Earth might completely disappoint us. Trend graphs for a comet's brightness fall short of expectations. Comets might approach very close to the sun before becoming visible here on Earth and break apart. Some comets might be extremely bright but can't be seen at night because of their proximity to the sun. Comets can approach very close to Earth but not have a large or bright enough coma or tail to be really appreciated without long exposure photographs using rather expensive gear. Comets might approach from above or below Earth's poles and that means only one hemisphere of Earth can view the comet, as was the recent case with McNaught. Occasionally, everything comes together perfectly like with Hale-Bopp, a particularly large comet that didn't get too close to the sun, was visible from Earth and stayed that way for months. Or in a more recent example, Comet Pan-STARRS in 2013. It made a relatively photogenic approach to the sun. For a time, we were able to observe a modestly bright comet with a well-developed tail for several weeks, but it just couldn't touch the fantastic views of Hale-Bopp. Hale-Bopp has a special place in my heart. For weeks during my sophomore year in high school, I'd watch as the comet would set outside my window. I'd download the latest pictures of the comet from our school computers on our brand new internet connection. I loved that comet. But today, I have cameras and astrophotography gear. I'm ready for the next big one, but we just don't know when that will be. But here comes Comet 2019 Y4 Atlas. And of course, it's 2020 and we're all feeling a little punished and beat up by what's happening. Don't panic though, this comet is perhaps a candidate for a neat new target for astronomy enthusiasts, or possibly a public spectacle everyone can enjoy. This comet is following roughly the same orbit as the Great Comet of 1844, which was a naked eye comet that approached quite close to the sun. A quick comment about comet names. Comets are named like this. The letter C or P, followed by the year of discovery and a two-digit code that represents when in that year, followed by the observer, astronomer, or astronomy program that discovered it. Atlas, in this case, is a near-Earth asteroid discovery program, while Y4 means that it was discovered at the very end of the year. December 28th, in fact. Comets Halebop, Hyakutake, West, and Halley are all named for the individual astronomers that discovered them. But they too have letter, year, and number designations that go with them. There are several comets named Atlas in the night sky observable right now with a modest telescope, so make sure Y4 follows the name when referring to this one. Let me tell you what we might see, what some of the failure modes might be, and how and when to look, especially if this little comet that could continues to overperform. I'll also be making a follow-up video and dive into more detail if this comet behaves or is starting to put on a good show. At this moment, 2019 Y4 Atlas is a magnitude 7 or 8 comet, depending who is measuring that brightness and with what method. But I'm going to assume you don't know what that means, so here's a primer on magnitude. Visual magnitude is a reverse scale. The very brightest objects, like the visible planets in our solar system, the very brightest stars like Sirius, the moon, and the sun have negative visual magnitudes, while the stars in your favorite and easiest constellations to spot, like Orion, have a magnitude around 0 to 2. Positive numbers are dimmer, and the higher the positive number, the harder that object is to see in the night sky. If you go way out away from city lights on a moonless night, then stars of magnitude 5 will be quite dim but visible. This includes the harder to see stars in the Little Dipper, for example. Magnitude 6 is roughly the brightness of the darkest objects the human eye can see in the night sky under the best possible conditions. But I'm going to be honest with you, any casual observer of the night sky won't be able to appreciate something like a comet in this magnitude 5 or 6 range. Naked eye visible at magnitude 5 or 6 is simply not going to impress anyone, present company included. Magnitude 7, 2019 Y4 Atlas, as of today, is not naked eye visible. It's not even that great of a target for most backyard telescopes. Photography, for the moment, is the best way to appreciate it. Your best option is a camera with a telescope or telephoto lens and a tracking mount with long exposures and stacking, which can yield results like this. By all means, if you have the equipment or some amount of skill with astrophotography, now is probably the time to start observing or photographing this comet, because things might be about to change quickly. 2019 Y4 Atlas is exceeding expectations right now. Even if we assume this is just some sort of outburst phase that the comet will grow out of soon, and it likely is, that still means we should be looking at a magnitude 2 comet a couple weeks before its closest approach to the sun. By comparison, Hale-Bopp was a magnitude 0 comet at its brightest, and most of the pictures you've probably seen of Hale-Bopp were while it was still a magnitude 2 or 1. But that definitely does not mean Comet 2019 Y4 Atlas will be as great of a sight as Hale-Bopp was. Let me tell the quick tale of two comets that have some similarities to 2019 Y4 Atlas. Comet 1973 E1, or Kohutek, received wide media coverage, hype if you will, that a brilliant comet of the century would grace the skies in December and January 1973 and 1974. While it did brighten to a maximum magnitude of minus 3, it only did so at the very closest approach to the sun when it was not visible for any Earth-based observers. And rather than becoming a spectacular naked-eye comet in the morning skies in December or the evening skies in January, it failed to be much more than just barely naked-eye visible. Worse, it looks as though the comet went through a partial breakup that made evening viewing in January even worse as the comet faded more quickly and began to retreat from the sun in its orbit. Two years later, having been burned by Kohutek's poor performance, media attention to Comet West was all but silent and West, by comparison dazzled, was even visible briefly in broad daylight and is widely considered one of the best comets seen in the modern era. And yet this event happened without much attention by the general public. Whoops! So even though lessons have been learned, more comets since then have been hyped only to not only fade in brightness but fade into obscurity or even vaporize into oblivion. So what happened? Comet Kohutek was unusually bright at the time of its discovery given its distance from the Earth and the sun, which led to high expectations. And a major letdown later. Comet ISON from 2013 had quite a similar story. So what then should we expect from Comet C2019-Y4-ATLAS? Well in this case it seems, so far at least, that the opposite is happening. Nothing terribly unusual was noted about its brightness during its discovery. The most interesting thing was that it was found to share the same orbit as the Great Comet of 1844. And if that's true, that means that this comet and the Great Comet of 1844 may actually just be fragments of an older, larger comet. Keep that in mind because if that's the case, this comet has experienced breakups before. 2019 Y4-ATLAS was and is so far exceeding expectations every single day, essentially since its discovery. At the time that I am doing this video, it has reached as good as a magnitude 7.1, or possibly as low as an 8.5. But this is when it was only supposed to be around a 12 or 11. That's around 500 times as bright as originally expected. More importantly, the minimum forecasted brightness of 2019 Y4-ATLAS this coming mid-May is now well within the naked eye visibility range. We can now pretty much expect, or hope for at least, a magnitude 2 or better comet in the evening western sky after sunset. But proceed with caution. Again, this is a newly observed comet, and comets love to fail to meet expectations. For some more context, 2011 L4-PANSTARRS graced the skies in March of 2013. It was a wonderful comet, but it didn't get a lot of attention outside of astronomy circles. It ever so slightly failed to meet the most rosy forecasts. The main problem with PANSTARRS wasn't really its brightness, rather that it was too close to the sun during the better parts of its show, meaning that you had to take photographs of the comet either during twilight, or while it was so low to the horizon that detail was getting lost in Earth's hazy thick atmosphere. 2019 Y4-ATLAS, on the other hand, should in theory brighten to around magnitude 2 or 3 at a time when it is still a fair amount above the western horizon for most people in the northern hemisphere. There's no moonlight to interfere at this time, and it can be observed for a short time after astronomical twilight. In other words, we should get to see this comet under more optimal conditions than 2011 PANSTARRS, which in my opinion is pretty fantastic. Given that we are looking at a short window of time to observe this comet, we need to plan our evening viewing this May ahead of time to get the most out of what this comet has to offer. To address the elephant in the room, yes, it should be possible to safely and discreetly watch the night sky in most places. Definitely check your local government's rules concerning where you can go and when you can observe. Even in places where you're being advised to stay home, driving alone at night to a place quiet and dark like a public park or public use land may be just fine, if not even encouraged as a healthy activity. Assuming things continue to track along nicely from here, in mid-April I'll make a follow-up video with much more detail. That's going to be the time for you to go out and look. But to summarize what might be in that next video, start paying close attention around April 20th during the next new moon. If we already have a naked eye visible comet at that time, then mid-May of 2020 should be very interesting. Check up on the latest magnitude observations of 2019 Y4 Atlas, and if the numbers are coming in at around a 6 or lower, then things are still going pretty well. In late April, 2019 Y4 Atlas will be difficult to find for anyone new to astronomy. You'll need to go out to a dark location outside of your city and away from street lighting. Familiarize yourself with the constellation Auriga, which will be setting in the northwestern sky after dark, and learn how to locate the bright star Capella. Learn to star hop with your eyes to find the location on the particular date you are observing. With some luck and practice, you should be able to find it with your eyes or a simple pair of binoculars. If things are going really well into early and mid-May, you shouldn't have to find it with the help of star charts anymore, and instead just look for a fuzzy ball in the northwestern sky. And if Atlas really puts on the show we are hoping for, May 15th to May 20th will be the best time to look. Wait until dusk, again look west, and the comet and its long shiny tail should start to make an appearance as the sky darkens. For the next month or so, you might see very dubious things said by the news or tabloids. It happens with every astronomical event. It's altogether a little too easy to make outright mistakes or offer bad astronomy or even worse. This comet won't come anywhere near Earth. It won't mean anything special. This kind of thing happens all of the time, many times in my lifetime in fact, during the best and worst of times. 2019 Y4 Atlas may be an amazing sight or a total dud, but nonetheless benign. Thanks for watching. Have a look around my channel and see if there's anything else that might interest you. Until then, my normal ending sounds terrible and erotic right now, so go play in the backyard I guess. I'm calling this one the Corona mullet. I guess it's time to check up on some self-haircut tips and tricks. Yep, he's a hot dog. Tucker, you're laying on my script. This isn't gonna work.