Green Comet Passing Earth Will Soon Be Visible to the Naked Eye

Comet C/2022 E3 (ZTF) as observed from Mount Fuji, Japan.
SpaceWeatherGallery.com/Akihiro Yamazaki

Now’s the time to start looking for Comet C/2022 E3 (ZTF) on clear, dark, moonless nights as it prepares to pass by Earth.

The Zwicky Transient Facility, aka ZTF, in Southern California discovered the dramatic object in March. It’d been speeding in the direction of the sun up until Jan. 12m when it reached perihelion, its closest pass by the sun, before beginning a long journey back to the Oort Cloud on the edge of the solar system.

According to Joe Rao from both Space.com and New York’s Hayden Planetarium, it won’t return for roughly 50,000 years. This makes January and February prime time to try to see it for yourself, perhaps even without the need of a telescope, if it continues to shine ever brighter. 

By some accounts, the comet is already visible to the unaided eye from very dark locations.

The latest reported observed magnitude for Comet C/2022 E3 (ZTF) is 5.9. Naked eye visibility from a dark site.

— David Blanchflower BSc (@DavidBflower) January 20, 2023

The comet is expected to be closest to Earth on Feb. 1, according to NASA, at which point it could become a magnitude five object, just bright enough to see with the unaided eye, though binoculars and very dark skies always help. 

Attached is a composition of the evolution of comet C/2022 E3.
I have labeled the days, distance from the Sun and distance from Earth. Courtesy Didac Mesa Romeu. pic.twitter.com/fzq4AAMLJe

— Con Stoitsis (@vivstoitsis) January 5, 2023

The behavior of comets is rather unpredictable, as they can brighten, dim or completely disintegrate with little warning. Comet ZTF’s coma, or tail, has already been observed appearing to split into two distinct tails in what astronomers call a “disconnection event.”

Amazing. Here’s a great animated capture of Comet C/2022 E3 ZTF’s recent tail disconnection event (along with lots of #Starlink streaks), courtesy of @Komet123Jager – https://t.co/VWeFpDf4U2 pic.twitter.com/EP6lY9kg9s

— Dave Dickinson (@Astroguyz) January 19, 2023

If trends and the integrity of the cosmic cruiser hold, the moonless sky on Jan. 21 could mark a good night to start venturing out to try to spot it, according to the British Astronomical Association. 

You can practice trying to spot the comet now with binoculars or a backyard telescope as it continues to brighten (hopefully) until Feb. 1. By far the easiest way to locate it is with a site like In The Sky or the excellent mobile app Stellarium. 

If you happen to get any great photos, please share them with me on Twitter, @EricCMack.