Rare green comet makes closest approach to the sun. How to watch it live tonight (Jan. 12).

A comet that hasn't visited Earth or the inner solar system since the last ice age will reach its closest point to the sun tonight (Jan. 12) and you can watch it live online in a free webcast.

The comet, designated C/2022 E3 (ZTF), will come to within around 100 million miles (160 million kilometers) of the sun as it reaches a closest point, called perihelion. The comet will then move towards Earth making its closest approach to our planet, its perigee, on Feb. 2 when it will whip past us at a distance of 26 million miles (42 million kilometers).

Though it won't be visible to the naked eye during its close approach to the sun, the comet should be observable with binoculars. If C/2022 E3 (ZTF) continues to brighten the way it currently is, it could eventually be possible to spot it in the night sky with the naked eye. Whether or not you'll be able to see it on your own, The Virtual Telescope Project will host a free livestream of the comet beginning at 11 p.m. EST on Jan. 12 (0400 GMT on Jan. 13). You can watch the live webcast courtesy of the project's website or on its YouTube channel. It will appear on this page at start time, as well.

Related: Amazing photos of gorgeously green Comet C/2022 E3 (ZTF)

NASA's Jet Propulsion Labs (NASA JPL) gives the period of this comet as 50,000 years. This means the last time the orbit of C/2022 E3 (ZTF) brought it so close to the Earth, our planet was in the midst of the last glacial period or "ice age" and early Homo sapiens and Neanderthals still shared the planet.

A photo of comet C/2022 E3 ZTF taken on Dec. 26, 2022 in Payson, Arizona by Chris Schur. (Image credit: Chris Schur)

A Celestron telescope on a white background

(Image credit: Celestron)

Looking for a telescope to see comet C/2022 E3 ZTF or anything else in the night sky? We recommend the Celestron Astro Fi 102 as the top pick in our best beginner's telescope guide

According to In the Sky from New York City C/2022 E3 (ZTF) at perihelion will be visible in the dawn sky, rising at 11:18 p.m. EST (0418 GMT) and reaching an altitude of 64° over the eastern horizon. The comet will fade from view as dawn breaks around 6:07 a.m. EST (1107 GMT). 

C/2022 E3 (ZTF) will eventually reach its brightest on Feb. 2 when it will be at its closest to Earth, visible in the constellation Camelopardalis. 

The comet was first identified in March 2022 by the wide-field survey camera at the Zwicky Transient Facility and was initially believed to be an asteroid. It was the rapid brightening of C/2022 E3 (ZTF) as it moved from the inner orbit of Jupiter that indicated it true cometary nature.

The brightening of comets can be difficult to predict, but even if C/2022 E3 (ZTF) doesn't brighten enough to become visible with the naked eye, it will still be observable during January and early February with binoculars and small telescopes. 

According to NASA observers in the Northern Hemisphere should be able to find C/2022 E3 (ZTF) in the morning sky, as it moves to the northwest throughout January. The comet will become visible for skywatchers in the Southern Hemisphere in early February 2023.

The new moon phase (when the moon is completely unilluminated) on Jan. 21 should provide the ideal dark skies needed to spot C/2022 E3 (ZTF), weather permitting. 

If you want to take a look at C/2022 E3 ZTF and don't have the right gear, be sure to peruse our guides for the best binoculars and the best telescopes to view the comet or anything else in the sky. For capturing the best comet images you can, we have recommendations for the best cameras for astrophotography and best lenses for astrophotography.  

Editor's Note: If you snap the comet C/2022 E3 (ZTF), and would like to share it with Space.com's readers, send your photo(s), comments, and your name and location to spacephotos@space.com.

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Robert Lea
Senior Writer

Robert Lea is a science journalist in the U.K. whose articles have been published in Physics World, New Scientist, Astronomy Magazine, All About Space, Newsweek and ZME Science. He also writes about science communication for Elsevier and the European Journal of Physics. Rob holds a bachelor of science degree in physics and astronomy from the U.K.’s Open University. Follow him on Twitter @sciencef1rst.

  • rod
    I observed this comet again, early today (10-Jan-2023).

    Observed 0145-0345 EST/0645-0840 UT. Waning gibbous Moon in Leo this morning, very bright. Last Quarter Moon 15-Jan-2023 0210 UT. Near 0150 EST I observed a bright meteor streak across the sky from Arcturus location moving WNW. Estimate apparent magnitude -1.0 and it left a train behind, illuminated by bright moonlight. This may have been a late Quadrantid meteor. They streak at about 41 km/s. I picked out the comet C/2022 E3 (ZTF) using 10x50 binoculars near 0200 EST. Faint fuzzy. The 90-mm refractor telescope provided better views. I observed from 25x to 71x. At 25x, the comet and star Kappa CrB visible in the eyepiece FOV. Kappa CrB near 7:00 position, the comet fuzzy near 2:00 position, north up and mirror reverse view. They were separated by about 64 arcminutes according to Stellarium 1.2. There was a distinct double star visible too, HIP77252 double star. The double star ~ 41 arcminute angular separation from C/2022 E3 (ZTF). At 71x, the comet had more coma and some tail visible. The lower power view at 25x was nice because I could see Kappa CrB and the comet together in the FOV along with some other fainter stars. Starry Night Pro Plus 8 shows mv +7.41, Stellarium 1.2 shows mv + 7.41, and theskylive.com reports an apparent magnitude 7.5. The skies clear this morning with west winds 5 knots and temperature -2C. Some foxes and deer were out moving about while I observed. I used TeleVue 40-mm plossl for 25x, TeleVue 32-mm plossl for 31x, and TeleVue 14-mm Delos for 71x observations. This is my third observation of C/2022 E3 (ZTF) since I started viewing 24-Dec-2022
  • CB_Melbourne_AU
    Where were you viewing from? Is the comet going to be visible in the Southern Hemisphere? I'm in Melbourne, Australia.
  • rod
    CB_Melbourne_AU said:
    Where were you viewing from? Is the comet going to be visible in the Southern Hemisphere? I'm in Melbourne, Australia.
    I view the comet in USA on east coast. The January issue of Sky & Telescope report by Bob King on page 48-49 shows the comet path. It is moving from Corona Borealis into Ursa Minor, passing not far from Polaris, into Camelopardalis in early February. These are northern hemisphere constellations.