There’s a new comet in the sky which is already creating a flurry of interest among amateur astronomers, visible at the end of January and early February 2023. Don’t get your hopes up too high, but just be pleasantly surprised if you manage to spot it with binoculars.But don’t expect to see it looking green as the media hype says!
Updated 14 February 2023
The comet is called C/2022 E3 ZTF, and it gets this jolly name from the time it was discovered and the instrument used to locate it. It is still visible using binoculars in the evening sky, but unless you have very dark skies the view is less than impressive and people just report seeing a faint circular glow.
Photographs (see below) show it with a green centre, which is quite common in comets due to the molecule cyanogen, (CN)2. However, even with a large telescope you are unlikely to see the colour. That’s the way it is, but the clickbait stories won’t tell you that.
Observers equipped with even small telescopes and cameras (and good tracking mounts) are still able to take pictures of the comet, which will reveal something of its green colour and maybe a faint tail. You will need a chart to be able to find it, but it’s currently about magnitude 7.
The comet was at its closest to Earth on 2 February when it was 48.5 million km from Earth.. Here are positions calculated by Chris Marriott’s SkyMap software for midnight (0 hours) on the dates shown. The distance shown is the distance from the Earth in astronomical units (the Earth–Sun distance) where 1 AU = 149,600,000 km.
Many news stories are saying that the comet was last seen during the Neolithic period. However, the orbital details don’t confirm this, and show it having a nearly parabolic orbit. The best we can say is that its period is indeterminate.
Ephemeris of comet C/2022 E3 ZTF
| Date | Top R.A. | Top Dec | Mag | Distance |
| 14 Feb 2023 | 04h 44m 33.6s | +18° 31′ 34″ | 6.9 | 0.4961 |
| 15 Feb 2023 | 04h 43m 26.1s | +16° 29′ 07″ | 7.0 | 0.5235 |
| 16 Feb 2023 | 04h 42m 30.3s | +14° 39′ 05″ | 7.2 | 0.5515 |
| 17 Feb 2023 | 04h 41m 44.2s | +12° 59′ 55″ | 7.3 | 0.5800 |
| 18 Feb 2023 | 04h 41m 06.5s | +11° 30′ 12″ | 7.4 | 0.6088 |
| 19 Feb 2023 | 04h 40m 35.8s | +10° 08′ 48″ | 7.5 | 0.6380 |
| 20 Feb 2023 | 04h 40m 11.2s | +08° 54′ 41″ | 7.7 | 0.6674 |
| 21 Feb 2023 | 04h 39m 52.1s | +07° 46′ 59″ | 7.8 | 0.6970 |
| 22 Feb 2023 | 04h 39m 37.6s | +06° 44′ 57″ | 7.9 | 0.7268 |
| 23 Feb 2023 | 04h 39m 27.4s | +05° 47′ 57″ | 8.0 | 0.7567 |
| 24 Feb 2023 | 04h 39m 20.9s | +04° 55′ 25″ | 8.1 | 0.7868 |
| 25 Feb 2023 | 04h 39m 17.7s | +04° 06′ 51″ | 8.2 | 0.8169 |
| 26 Feb 2023 | 04h 39m 17.5s | +03° 21′ 52″ | 8.3 | 0.8471 |
| 27 Feb 2023 | 04h 39m 20.1s | +02° 40′ 04″ | 8.4 | 0.8773 |
| 28 Feb 2023 | 04h 39m 25.1s | +02° 01′ 10″ | 8.6 | 0.9075 |
Gallery
Shown below are finder charts for the comet. Bear in mind that if you are observing before midnight, the comet will be close to the position for midnight on the following date.
