How to See the Bright Green Comet 21P in Binoculars on Monday

Want to see a comet whizzing by Earth? A great chance to catch one of these celestial visitors is overnight tonight, when Comet 21P/Giacobini-Zinner will be best visible in binoculars or a telescope.

The comet, also known as "21P," will make its closest approach to Earth at around 2:30 a.m. EDT Monday (630 GMT). The bright-green comet should reach a visual magnitude of 6.5 to 7, according to This makes 21P almost bright enough to see with the naked eye — but not quite. [Bright Comets of 2018: When, Where and How to See Them]

Look up with binoculars early tomorrow morning (Sept. 10) to spot Comet 21P/Giacobini-Zinner whizzing across the sky. Here, astrophotographer Alexander Vasenin caught a photo of the comet from Moscow Oblast, Russia, on Aug. 18, 2018. (Image credit: Alexander Vasenin/Wikimedia Commons/CC BY-SA 4.0)

To find Comet 21P in the night sky, look east and find the constellation Auriga sometime between midnight and dawn local time. The comet will still be visible even after tomorrow, but it will fade over the coming days. Its exact location from moment to moment is available in NASA's ephemeris calculator.

Comets are small bodies of ice and dust that orbit the sun, just like the planets do. But comets are much smaller than planets, and they travel in highly elliptical orbits. Comet 21P goes around the sun every 6.6 years, and its trail of dust and debris is the source of the annual October Draconid meteor shower.

This sky map shows the approximate location of Comet 21P/Giacobini-Zinner during its closest approach to Earth, on Sept. 10, 2018, at 2:27 a.m. EDT (0627 GMT), as seen from New York City. (Image credit: SkySafari App)

Meteors are space dust or space rocks that plow into Earth's atmosphere. Meteor showers usually happen when the Earth moves across the path of dust left behind by a comet or asteroid. While some meteor showers produce dozens of "falling stars" or more every hour, the Draconids are fairly weak. The shower is expected to generate only up to eight shooting stars per hour in 2018, NASA meteor expert Bill Cooke told [Amazing Photos of Comet 21P/Giacobini-Zinner and Comet 46P/Wirtanen]

Even if you don't own a pair of binoculars or if you miss out on Comet 21P for any other reason, don't worry: You'll likely have the chance to watch another green comet later this year. Comet 46P/Wirtanen will make its closest approach to the sun on Dec. 16, and current predictions say the comet will be visible with the naked eye. You can see more information about 46P in this recent story. You can also see some pictures of the two approaching comets here.

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Elizabeth Howell
Staff Writer, Spaceflight

Elizabeth Howell (she/her), Ph.D., is a staff writer in the spaceflight channel since 2022 covering diversity, education and gaming as well. She was contributing writer for for 10 years before joining full-time. Elizabeth's reporting includes multiple exclusives with the White House and Office of the Vice-President of the United States, an exclusive conversation with aspiring space tourist (and NSYNC bassist) Lance Bass, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, flying parabolic, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, "Why Am I Taller?", is co-written with astronaut Dave Williams. Elizabeth holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, a Bachelor of Journalism from Canada's Carleton University and a Bachelor of History from Canada's Athabasca University. Elizabeth is also a post-secondary instructor in communications and science at several institutions since 2015; her experience includes developing and teaching an astronomy course at Canada's Algonquin College (with Indigenous content as well) to more than 1,000 students since 2020. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday. Mastodon: