Want to watch green Comet C/2022 E3 (ZTF) flying past Earth and Mars? Tonight is the time to see!


While it has been visible with the help of binoculars since the start of the month, Comet E3 is now at one of its closest points to Earth. Although the comet was nearest to our planet last Wednesday evening (1 February 2023), passing within 42 million kilometres, it will still be visible in the northern hemisphere tonight.

But there's a catch. Although the comet – last seen in our skies 50,000 years ago – sounds like a celestial spectacle you won’t want to miss this evening, a bright Moon (February's snow Moon, to be exact) will make visibility difficult. But not impossible... if you know how.

With the help of Dr Darren Baskill, astronomer lecturer at the University of Sussex, we explain exactly when Comet E3 can be seen, where it can be spotted and what it actually looks like.

Plus, if you want to make the most of the night sky this year, check out our meteor shower calendar, astronomy for beginners guide and UK full Moon calendar to make the most of the night sky.

When can I see the green Comet E3 tonight in the UK?

In the UK, the comet is best seen between 6:30pm and 10:15pm tonight (10 February 2023). "During this time, the Moon won't have risen yet and the comet will be visible close to Mars," explains Baskill.

And it's the Moon that's your biggest barrier to seeing the comet. “Trying to view Comet E3 while the Moon is in the sky will be difficult, especially in a humid spot like the UK. In a damp climate, there’s always a bit of haze that reflects moonlight and drowns out the view of faint objects,” Baskill says.

"The Moon will be interfering, but it's still worth a look to see the comet."

The best time to see the comet was between 5.30am and 6.30am on 2 February 2023, when it passed closer to Earth. However, don't worry if you missed this – Comet E3 may still appear in the night sky for another week.

Where do I need to look to see Comet E3?

This depends on when you’re looking. If you are trying to see the green comet on 10 February, it can be found close to the star Capella, in the northern constellation of Auriga, and Mars.

If you’re struggling to find this point in the sky, we recommend using an app such as Skylite (available for free on Android and Apple devices) – see other available apps in our best astronomy apps guide.

On 10 February, the comet will pass the planet Mars. “Look for a bright red object in the sky with your binoculars and you’ll see it nearby!” says Baskill.

How to see the green comet e3 tonight
© Darren Baskill

Do I need a telescope or binoculars to see Comet E3?

Comet E3 has a brightness magnitude of +6, which means it should technically be visible to the human eye. However, the brightness of the Moon will make it harder to see.

“That means you need a telescope or binoculars – but nothing too fancy,” says Baskill.

He adds: “The good thing about the Moon being so bright is that your back garden is as good as anywhere to see the comet. That’s because even if you went in the middle of a country park away from the light pollution of the city, the moonlight would still be the biggest visibility problem.”

Comet C/2022 E3 (ZTF) is visible in the sky above the Mojave National Preserve in San Bernadino County as it approaches Earth for the first time in about 50,000 years on January 31, 2023 near Baker, California
Comet C/2022 E3 (ZTF) pictured in the sky above the Mojave National Preserve in San Bernadino County as it approaches Earth for the first time in about 50,000 years on January 31, 2023 near Baker, California. © Ethan Miller/Getty Images

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How green is Comet E3?

If you’re looking at Comet E3 with a telescope or binoculars, the comet will appear as a faint fuzzy object with a green core and white surroundings.

“The green is due to the chemical composition of the comet and chemicals called diatomic carbon and cyanogen,” explains Baskill.


“All the atoms in the Universe glow their own characteristic hues – it allows us to work out what the entire Universe is made out of, just by looking at the colours.”

About our expert, Dr Darren Baskill

Dr Darren Baskill is an outreach officer and lecturer in the department of physics and astronomy at the University of Sussex. He previously lectured at the Royal Observatory Greenwich, where he also initiated the annual Astronomy Photographer of the Year competition.

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Thomas Ling
Thomas LingDigital editor, BBC Science Focus

Thomas is Digital editor at BBC Science Focus. Writing about everything from cosmology to anthropology, he specialises in the latest psychology, health and neuroscience discoveries. Thomas has a Masters degree (distinction) in Magazine Journalism from the University of Sheffield and has written for Men’s Health, Vice and Radio Times. He has been shortlisted as the New Digital Talent of the Year at the national magazine Professional Publishers Association (PPA) awards. Also working in academia, Thomas has lectured on the topic of journalism to undergraduate and postgraduate students at The University of Sheffield.