Is the comet still visible? Comet Tsuchinshan-ATLAS is no longer a naked-eye object, but if you have binoculars or a small telescope, it’s still worth finding.
This long-period comet from the Oort Cloud — a sphere around the solar system home to millions of comets — astronomers think it loops around the sun once every 80,000 years.
Also known as comet A3 and C/2023 A3, this snowball from the depths of the solar system has a central coma 130,000 miles (209,000 kilometers) in diameter. It also has a trademark tail extending 18 million miles (29 million kilometers).
Although its magnitude of +3.4 makes it technically visible to the naked eye, this comet is rapidly getting fainter and smaller as it returns to the Oort Cloud. Tonight it will be 79 million miles (127 million kilometers) from the sun and 78 million miles (125 million kilometers) from Earth.
However, if you know when and where to look, it can still be found in the constellation Ophiuchus. As a bonus, it’s now visible in a dark sky, with last week’s supermoon no longer bleaching the night sky. Here’s how to photograph the comet with a camera or a smartphone.
Note: times and viewing instructions are for observers at mid-latitudes in the Northern Hemisphere. Check the exact time of sunset where you are and the comet’s setting times on Stellarium Web for times that are accurate for your exact location.
How To Locate Comet Tsuchinshan-ATLAS: Sunday, Oct. 27
Position: west, 54 degrees from the sun in Ophiuchus
Time: from 60 minutes after sunset where you are until about 22:15 local time
Magnitude: +3.4
Comet’s distance from the sun: 79 million miles (127 million kilometers)
Comet’s distance from Earth: 78 million miles (125 million kilometers)
So far, the guiding lights to find the comet have been the bright planet Venus and the bright red star Arcturus. However, as October draws to a close, both are so close to the horizon an hour after sunset that they’re unlikely to be visible. So, instead, use the stars of the Summer Triangle to find the comet. Vega in the constellation Lyra should be easy enough to find above due west and, above it, Deneb in Cygnus.
How To Find The Comet Using The Summer Triangle
Look to the left of both, and you’ll see Altair in Aquila. Make a rough triangle between Altair and Vega pointing down to the horizon — the third point is roughly where the comet will be. You’ll need binoculars to see it — as well as a dark, clear sky.
How To Find The Comet Using Vega
Draw an imaginary line straight to the horizon from Vega and make a coat-hangar shape on the left — the comet will be the hook to the side. Scan with a pair of binoculars until you find it.
Check my feed every day this week and next for a daily “comet tracker” with sky charts and tips for viewing the comet.
Wishing you clear skies and wide eyes.
