The passing of a comet can bring feelings of either dread or wonder. A mysterious celestial event known as the Star of Bethlehem — which was said to have accompanied the birth of Jesus Christ — could have been a comet because it appeared so suddenly, stayed for so long and was seen crossing the sky. More recently, science fiction movies like "Deep Impact" depict comets the size of Mount Everest on a collision course with Earth, prompting more contemporary characterizations of apocalyptic scenarios.
Yet throughout late September and mid-October, a person can watch a much-anticipated comet known as Tsuchinshan-ATLAS (official name: C/2023 A3) with neither religious awe nor fear of existential doom. The most important thing you'll need to know where to look and have a good view of the horizon, according to Nick Moskovitz, an astronomer at Lowell Observatory in Flagstaff, Arizona.
"It should be bright enough to see with the naked eye, kind of starting today through early next week before it gets too close to the Sun," Moskovitz told Salon. "It'll be visible as a very early morning comet. So you have to get up right before sunrise for maybe an hour or so, and look off to the eastern horizon. You need to be able to see a good vantage all the way to the eastern horizon. And again, about an hour before sunrise, you may be able to see it."
This will be helpful throughout the weekend, but by Monday folks in the northern hemisphere will not be able to easily spot Tsuchinshan-ATLAS again for the next few days. The good news for them is that, around Oct. 12, Tsuchinshan-ATLAS is expected to be visible again all over the planet.
According to Astronomy Magazine, it may be a "more productive option" for northern hemispheric stargazers to plan on catching Tsuchinshan-ATLAS both this weekend and in mid-October, since the latter occasion could prove more fortuitous. After passing within the boundaries of the constellation Virgo, Tsuchinshan-ATLAS will go on a trajectory through Serpens and the constellation Ophiuchus before eventually, on Oct. 28th, lying just south of the second-brightest star in the constellation Ophiuchus, magnitude 2.8 Cebalrai. Some are predicting it will be so bright, it could be the "comet of the century."
Yet this is not to say that it will be easy to spot Tsuchinshan-ATLAS on any of these occasions — at least without a trusty pair of binoculars or low-powered telescope. Moskovitz ruefully noted that the comet can be "pretty hard to see, actually, because it's essentially a daytime comet, which means as it gets brighter over the next few weeks, it's going to be close to the Sun. The Sun, as you might imagine, acts as a big source of glare that makes it hard to see small and faint things nearby."
Despite these disadvantages, stargazers should count their blessings. This is the first time that Tsuchinshan-ATLAS will be visible without a telescope in 80,000 years, which is how long it takes to orbit the Sun. It has likely been around for a long time, which makes comets like this even more intriguing to astronomers.
"Comets are really interesting because they're kind of what we think of as pristine relics of the ancient solar system," Moskovitz said. "Back before there were even planets around the Sun, there were what we would call planetesimals, the very building blocks that created and built up the planets that we have today. And comets are some of these leftover relics of that time in the very early era of the solar system. So by studying objects like this comet, we can understand what the conditions were like when they formed and what kind of materials were involved."
