Astro-Observer

Finding Comet C/2023 A3 in October 2024

By Astro-Observer · Last reviewed November 8, 2026

Comet

This article was written for the appearance of Comet C/2023 A3 (Tsuchinshan-ATLAS) in October 2024.

A Guide for Skywatchers

Comet C/2023 A3 (Tsuchinshan-ATLAS) is generating excitement among astronomers and stargazers alike. Independently discovered by China's Tsuchinshan (Purple Mountain) Observatory and the ATLAS survey in early 2023, it makes its closest approach to Earth, about 70 million kilometers, on October 12, 2024. The comet is expected to be a stunning spectacle, possibly visible to the naked eye, and is considered a not-to-be-missed celestial event.

Here’s everything you need to know to track Comet C/2023 A3 during its approach in October 2024.

Path of the Comet

Comet C/2023 A3 has a long, elliptical orbit that will bring it relatively close to Earth during its pass in late 2024. The comet passes perihelion—its closest approach to the Sun—on September 27, 2024, and should be at its brightest in early to mid-October. The best time for evening observation will be from about October 12 into late October, as it climbs higher in the sky and slowly fades.

Location in the Sky: The comet starts out in the morning sky and then switches to the evening sky.

  • Late September and early October: The comet will be low in the east before dawn, in Sextans and near the hind feet of Leo, very close to the horizon in bright twilight. Around October 9 it passes nearly between the Earth and the Sun and is lost in the Sun's glare.
  • Mid-October: The comet reappears low in the west just after sunset around October 12. It moves from Virgo into Serpens Caput around October 15, climbing higher each evening.
  • Late October: The comet moves into Ophiuchus around October 19 and keeps fading as it moves away from the Sun and Earth.

In October, skywatchers should look toward the western horizon just after sunset to spot the comet.

How to Observe

To find Comet C/2023 A3, one must track its nightly shifting positions in the sky. For optimal viewing, consider the following steps:

  1. Use Binoculars or a Telescope: While it may become visible to the naked eye, starting with binoculars or a telescope will provide a much better view of the comet’s nucleus and its tail. Binoculars with 7x or 10x magnification are ideal for spotting the comet’s coma and faint features.
  2. Consult Star Charts or Astronomy Apps: Astronomy apps like SkySafari, Stellarium, or Star Walk can help track the comet’s precise location in real-time. These tools will overlay the comet’s position on the night sky, making it easier to spot.
  3. Timing: The best viewing times will depend on your location and light pollution. If you are in a rural area with minimal artificial lighting, you may see the comet with the naked eye. However, city-dwellers may need to rely on a telescope or binoculars. The ideal time to observe the comet will be just before dawn in early October and just after sunset from mid-October on, depending on its location in the sky relative to the Sun.
  4. Weather Conditions: Clear, dark skies are critical for observing the comet. Check your local weather forecast and try to observe during nights with minimal cloud cover. Be prepared to adjust your observation time based on weather conditions.

Potential Brightness

Forecasts suggest that Comet C/2023 A3 may become brighter than magnitude 4, making it visible to the naked eye in favorable conditions. Nonetheless, comets are infamously erratic, and their true luminosity can fluctuate. As sunlight and the solar wind drive gas and dust off the comet near the Sun, it might show a long, luminous tail in mid-October.

The comet’s coma, the cloud of gas and dust surrounding the nucleus, could also become visible, giving the comet its characteristic "fuzzy" appearance.

Viewing Tips for Skywatchers

  • Find a Dark Sky Location: Light pollution can dramatically reduce your ability to see celestial objects like comets. If possible, head to a dark sky area away from city lights.
  • Use Red Light for Navigation: When observing the sky, use a red light to read star charts or check your equipment. Red light preserves your night vision, making it easier to spot faint objects like comets.
  • Be Patient: Finding a comet can take time, especially as it moves across the sky. Start looking a bit before the predicted viewing time, and don’t be discouraged if you don’t spot it immediately.

Comet C/2023 A3 presents a unique chance for sky enthusiasts to observe a celestial body that may shine brilliantly. Its emergence in October 2024 is an event not to be overlooked, whether you are a seasoned astronomer or simply enjoy gazing at the stars. Be sure to have your binoculars or telescope ready, consult your star charts, and revel in the splendor of this spectacular natural phenomenon as Comet C/2023 A3 brightens the night sky.

Postscript: The comet survived its pass around the Sun and was a fine naked-eye sight with a long tail in mid-October 2024, before fading toward the end of the month.