Comet C/2023 A3

Don’t look now, but comet C/2023 A3 might just be coming our way. Just recently this comet, also known as Tsuchinshan-ATLAS, was seen close to the Sun. It will reach perihelion – its closest approach to the Sun – on September 27.

There is a chance – a chance – that it might be visible to the naked eye as it travels around the Sun in very late September (east to southeast just before sunrise) and back out toward the Earth in mid to late October (west to southwest just after sunset). See Brian Ventrudo’s article (Cosmic Pursuits) for charts showing the comet’s location. We will update this article with more information as it becomes available (and hopefully a few images).

The latest news (September 23) indicates that the comet might be visible on September 29 (Friday) and September 30 (Saturday) at around 30 minutes before sunrise in the southeast. For most of us, it will then disappear in the glow of the Sun and reappear low in the western horizon around October 12.

As of October 7, we’re still expecting the comet to be visible (evenings in the west beginning on Thursday, October 11). One of our members found an article that gives more information.

On Sunday, October 13, some of the club members found the comet in the western horizon during twilight. A few of their images are below.

^{Image Credits: Joe Haberthier and Bill Rankin}

On Monday, October 14, the comet was faintly visible to the naked eye. Here are a few more images including two from a Seestar S50.

^{Image Credits: Joe Haberthier, Bill Rankin and Bruce Gavett}

On Wednesday October 16, the comet was not a visible to the naked eye. However, a couple members did capture a few images using their Seestar S50s. Notice the “2nd tail” in the image to the right. This is not the actual comet tail, but more of an illusion.

^{Image Credits: Bruce Gavett and Bill Rankin}

We’ll round all this out with a few more images taken by our members.

^{Image Credits: Joe Haberthier, Bill Rankin, and Steve Childers.}

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Comets are objects left over after the formation of the Solar System and consist of frozen gas, dust, rock, and ice. Their nucleus might be a mile to several miles in diameter. Comets heat up as they get close to the Sun and develop a planet sized ”coma” of gases. Pressure from the Sun’s light and the solar wind also produces two tails, which extend for millions of miles.

• One is the ion tail, which is created by the solar wind, composed of gases, is usually blue in color, and points away from the Sun.
• The other is the dust tail, which is illuminated by the Sun’s light and curves back toward the orbit of the comet.

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Below are images of an earlier comet C/2020 F3 (NEOWISE) taken by two of our members (Dave Morgan and Joe Haberthier) a few years ago.

Just to be clear, comets don’t always behave as we’d like them to. There is the old saying: “Comets are like cats, they have tails and go where they want to.”