Comet C/2023 A3 (Tsuchinshan-ATLAS) rises above a tranquil Mount Etna in this photograph taken on October 20, 2024. Credit: Gianni Tumino
Comet C/2023 A3, better known as Tsuchinshan-ATLAS, is fading in brightness as it moves away from the Sun and Earth in the evening sky. It is still visible to the naked eye in a dark sky and is definitely an easy target for binoculars. But this is your last chance to see it, so go out and take advantage of it while you can.
Here’s where the comet will be 45 minutes after sunset on the following dates. While the numbers here are specific to Tucson, Arizona, they should be accurate enough to help you spot the comet no matter your location.
| October date | Comet altitude | Azimuth of the comet |
| 21 | 35° | 248° |
| 22 | 37° | 247° |
| 23 | 38° | 245° |
| 24 | 39° | 245° |
| 25 | 40° | 244th |
| 26 | 41° | 243rd |
The azimuth tells us where the comet is relative to the cardinal directions (north, south, east, west). An azimuth of 0° is due north and 270° is due west. So, for example, if you’re looking for the comet 45 minutes after sunset on the 22nd, look 23° south of west and 37° above the horizon.
If you make a fist and hold it at arm’s length, its distance from top to bottom measures approximately 10°. So, on the 25th, 45 minutes after sunset, the comet will be a little taller than four of your fists, stacked on top of each other, if you place the bottom of it along the western horizon.
Good luck and send your photos to readergallery@astronomy.com – we will feature the best ones on the website and perhaps in the magazine.
