Comet C/2023 A3 (Tsuchinshan-ATLAS) is getting closer to its nearest point to the sun, which likely means it will also get close to Earth.

The comet will be at its most luminous approximately 36.4 million miles from the sun starting September 27. However, astronomy enthusiasts can expect the best sightings of the comet from early to mid-October, as reported by Astronomy Magazine.

C/2023 A3 is particularly exciting for astronomers and amateur stargazers since it is a long-period comet, taking over 200 years to complete an orbit around the sun (in contrast to short-period comets that take less than 200 years).

This comet was initially seen by the Purple Mountain Observatory on January 9, 2023. It was also detected by the Asteroid Terrestrial-impact Last Alert System (ATLAS) in South Africa.

After its discovery, the comet has made its way toward the sun, reaching its closest point — perihelion — on September 27. Its nearest approach to Earth will take place on October 11 or 12, according to BBC Sky at Night, but it will still be about 44 million miles away.

Path of Comet C/2023 A3

The animated graphic below illustrates the trajectory that C/2023 A3 will follow as it orbits near Earth, depicted by the dashed line representing its estimated path into the inner solar system.

What constitutes a comet?

Comets are icy remnants composed of dust, rocks, and ice from the early solar system, according to NASA. As they draw nearer to the sun, they heat up and emit gas and dust, creating a bright halo around them. Their tails can extend from a few miles to several hundred miles long.

How to locate C/2023 A3 in the night sky

For those in the Northern Hemisphere, the comet C/2023 A3 will be visible in the constellation Sextans, rising about an hour before sunrise, as noted by Astronomy.com.

The optimal time to observe the comet will be in mid-October, as it will ascend from the western horizon and be visible in the southwestern sky at nightfall, weather permitting. This will likely be its brightest display until it begins to dim around November 7, according to SkyandTelescope.com.

Ideal viewing times for the comet

Comet visibility can be erratic. While C/2023 A3 may be seen without binoculars, using a good pair of binoculars or a small telescope can enhance the viewing experience.

Deciphering the comet’s name

The International Astronomical Union (IAU) has a specific naming convention for comets that appears complex at first glance but is systematically organized:

Notation on orbit length

The letter “C” does not signify “comet,” rather it classifies this comet as a nonperiodic one with an orbital period exceeding 200 years.

Other prefixes include:

• P: Periodic (or short-period) comet that completes a solar orbit in less than 200 years.
• A: An asteroid or minor planet previously classified as a comet.
• X: A comet with an incomputable orbit.
• D: A periodic comet that no longer exists or has vanished.
• I: An interstellar object.

Year of Discovery

Next comes the year the comet was discovered.

Month of Discovery

The combination of letter and number indicates the month in which the comet was discovered.

• Letter: The IAU assigns letters A through Y to each half of the month (e.g., January 1-15 is “A,” and January 16-31 is “B”). Note: “I” is excluded to avoid confusion with the numeral 1, and “Z” is not used either.
• Number: Represents the order of discovery within that half-month.

Thus, “A3” in C/2023 A3 indicates this comet was found in the first half of January 2023.

(Discoverers of the Comet)

Finally, the comet’s discoverer is noted in parentheses. In this case, it was first located by the Purple Mountain Observatory on January 9, 2023, and later rediscovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) in South Africa on February 22, 2023. These observations help astronomers gather information about various celestial bodies.

SOURCE NASA, Space.com; EarthSky.org, UniverseToday.com,

Reports and research from the International Astronomical Union, TheSkyLive.com, LiveScience.com, SkyandTelescope.com, and YSL News Network