Democracy Dies in Darkness

How to see the once-in-80,000-year-comet before it’s too late

Comet Tsuchinshan–ATLAS is expected to be visible for the next few weeks after making its its closest approach last Saturday.

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Comet C/2023 A3 (Tsuchinshan-ATLAS) appears in the western sky shortly after sunset above rock formations in the Red Rock Canyon National Conservation Area in Las Vegas on Monday. (Ethan Miller/Getty Images)
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An ancient comet is gracing our night skies this month. Catch it now because it won’t be back for another 80,000 years.

Comet Tsuchinshan–ATLAS, discovered in 2023, is expected to be visible for the next few weeks after making its closest approach last Saturday. It is the brightest comet since Neowise in 2020, which was widely seen with the naked eye, including in busy cities.

The comet will travel higher and higher in the sky each night until around Halloween, making it dimmer and more difficult to see. The comet will be visible to the naked eye, but it will be best to view it through binoculars.

People in the northern hemisphere — including around D.C., Maryland and Virginia — have already spotted the bright comet streaking through the sky.

Here’s what to know about the rare comet.

What is the Tsuchinshan-ATLAS comet? When was it last visible?

Comet Tsuchinshan–ATLAS was identified in 2023 by two observatories, which are also its namesake. China’s Tsuchinshan (or “Purple Mountain”) Observatory and an ATLAS (Asteroid Terrestrial-impact Last Alert System) telescope in South Africa documented it for the first time in history as it approached the inner solar system.

The comet’s tail is about 18 million miles long.

The comet comes from the Oort cloud, an invisible cosmic cloud that encompasses the sun and planets. It is thought to have been seen last more than 80,000 years ago, when Neanderthals walked the Earth.

When and where will it be visible this week?

The comet will be best seen from now through Oct. 26. Look west, and find dark skies for the best views of the comet.

It will be visible in cities, even with light pollution, but will be primarily visible in darker skies later on in the month.

The comet will be visible a few minutes before sunrise or a few minutes after sunset — and binoculars or even a basic telescope will be helpful to spot it in the sky.

The bright light from the moon may make it more difficult to spot the comet, but conditions should be better after the full moon Oct. 17.

Will you be able to view it from the D.C. area?

Many people have already seen it from the D.C. area, including from the national Mall, Reston, Va., Leesburg, Va., and Poolesville, Md.

This week is the best week to see it in D.C., according to a newsletter written by sky watcher Tony Rice. The comet is expected to be half as bright this weekend.