Can You See Comet Tsuchinshan-ATLAS?
By Graham Jones. Published 27-Sep-2024
A comet with a strange-sounding name might be visible to the naked eye in the coming weeks.
You can use our Night Sky Map to find Tsuchinshan-ATLAS from your city. This is the view toward the western horizon from New York at 20:00 (8 pm) local time on October 15, 2024. (The size of objects is exaggerated to show their positions more clearly.)
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Find Comet Tsuchinshan-ATLAS on our Night Sky Map
A Rare Naked-Eye Comet?
Comets are small, icy bodies that orbit the Sun in highly elliptical, or oval-shaped, orbits. When a comet passes close to the Sun, it warms up, and can produce a tail of gas and dust.
Thousands of comets have been discovered—but only a handful of them ever become visible to the naked eye.
One comet that might be visible to skywatchers over the coming days and weeks is called C/2023 A3 (Tsuchinshan-ATLAS).
Try Catching It in October
Tsuchinshan-ATLAS will make its closest approach to the Sun on September 27, 2024. Around this time, it might be faintly visible before sunrise, close to the eastern horizon.
This is the view to the east from New York at 06:00 (6 am) local time on September 27, 2024. The position of Tsuchinshan-ATLAS is close to the horizon, below the Moon.
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Soon after this, the comet will pass between Earth and the Sun and become lost from sight. It might reappear in October, appearing low in the western sky after sunset.
The best time to spot Tsuchinshan-ATLAS may be in mid-October, after the comet makes its closest approach to Earth on October 12, 2024.
Throughout October, Tsuchinshan-ATLAS will get farther from the Sun—and appear higher above the western horizon in the evening sky. This is the view from London at 20:00 (8 pm) local time on October 22, 2024. (The size of objects on our Night Sky Map is exaggerated to show their positions more clearly.)
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Why all the “mights” and “maybes?” It’s because comets are notoriously difficult to predict—we cannot be certain how bright Tsuchinshan-ATLAS is going to become.
Find Comet Tsuchinshan-ATLAS on our Night Sky Map
What Does the Name Mean?
The name C/2023 A3 (Tsuchinshan-ATLAS) is based on a set of rules from the International Astronomical Union.
- C/ refers to a non-periodic comet. This means the comet hasn’t been observed before, and its orbital period (the amount of time it takes to complete one orbit around the Sun) is greater than 200 years. The orbital period of C/2023 A3 is thought to be around 80,000 years.
- 2023 is the year the comet was discovered.
- A indicates the half-month it was discovered. The first half of January is “A,” the second half of January is “B,” the first half of February is “C,” and so on.
- 3 means it was the third comet discovered in the first half of January.
- Tsuchinshan-ATLAS tells us it was discovered by two observatories. A system of robotic telescopes called the Asteroid Terrestrial-impact Last Alert System (ATLAS) spotted the comet on February 22, 2023. When the orbit of the comet was calculated, astronomers noticed it matched an object reported by the Purple Mountain Observatory in China on January 9, 2023. “Tsuchinshan” is a way of writing the Mandarin words for “Purple Mountain”.