On October 14th to 24th, astronomy enthusiasts are in for a rare cosmic treat as Comet C/2023 A3 (Zijinshan-Atlas) makes its appearance in the night sky of the Northern Hemisphere. The comet can be seen low in the western sky shortly after sunset, presenting an exceptional opportunity for stargazers to observe this phenomenon with the naked eye. With an orbital period of over 10,000 years, this means it will be a millennium before we see it again.
According to NASA, Comet C/2023 A3 was jointly discovered in 2023 by the Zijinshan Observatory in Nanjing, China, and the ATLAS asteroid observation system. This ancient and mysterious comet is believed to originate from the Oort Cloud, a vast region surrounding our solar system filled with interstellar debris and celestial bodies. The Oort Cloud, which is extremely distant, contains billions of icy objects, and many such comet-like bodies rarely approach Earth within their thousands or even tens of thousands of year-long orbits. The orbit of this particular comet takes approximately 60,000 to 80,000 years to complete one circuit around the sun, making it one of the most anticipated comets of 2024.
Starting from October 12th, Comet C/2023 A3 has been shining brightly in the western sky shortly after sunset, positioned low and near the constellation Virgo. It has reached a brightness of negative magnitude, offering an ideal viewing opportunity. Many astronomy enthusiasts in the San Francisco Bay Area have already spotted the comet crossing the sky and have even managed to capture images with just their smartphones.
From October 13th to 14th, the comet’s brightness began to decline, ranging from 0 to 1 magnitude. However, given its distance from the sun, observations became somewhat easier. On October 15th, the comet was expected to come very close to the M5 globular star cluster, providing photographers with a fantastic opportunity. Additionally, a phenomenon known as a “anti-tail” might occur, where a bright streak points toward the sun, opposing the traditional tail of the comet.
Scientists predict that the brightness of the comet will continue to wane over time. From October 20th to 31st, the brightness is expected to drop from 4.5 to 7 magnitude, during which its tail will become noticeably longer. For astronomy enthusiasts eager to catch a glimpse of the comet, finding an open area away from city lights after sunset will increase the chances of viewing. NASA recommends using binoculars or a small telescope for better observations. For those looking to capture clearer photographs of the comet, utilizing the long exposure feature on cameras can yield impressive results.
