Science: Both amateur and professional astronomers are pleased with the spectacular display provided by comet 2024 G3 (ATLAS) in mid and late January. After its closest pass to the sun (perihelion) on January 13, the comet became very bright and soon thereafter developed a tail with significant and strong structure.
Discovered by the Asteroid Terrestrial Impact Last Alert System (ATLAS) on April 5 in images obtained from the 19.7-inch (0.5-meter) reflector telescope located in Rio Hurtado, Chile, the comet met or even exceeded expectations to become the brightest comet in 18 years. For several days it was visible from most locations in the Northern Hemisphere with clear, transparent skies and clear, unobstructed horizons.
In addition, C/2024 G3 (ATLAS) is one of the few comets on record that became bright enough to be visible during the daytime without optical aid.
Unfortunately, for those north of the equator, the opportunity to catch a glimpse of the comet was fleeting, lasting only a week, centered on the day of perihelion. For most of its time, C/2024 G3 (ATLAS) has been primarily held by Southern Hemisphere skywatchers.
In early January, the comet was estimated to be shining at about third magnitude, or about as bright as a moderately bright star. But on January 2, according to veteran Australian comet observer, Terry Lovejoy, the comet was apparently in the midst of an explosion in brightness, and in fact just one day later, it had brightened by almost a full magnitude to +2; about as bright as Polaris the North Star, a nearly threefold increase in brightness.
Becoming Increasingly Difficult to See
By January 7, the comet had reportedly reached first magnitude, with a tail about half a degree in length (about equal to the apparent diameter of the Moon). However, by then ground observations were becoming difficult due to the comet’s proximity to the Sun, as the comet’s altitude caused it to get closer to the east-southeast horizon each morning, and also to sink into the bright darkness of dawn.
