Brightest comet for 13 years now in UK skies

There’s a bright comet in our skies, which is visible to the naked eye during July in the evening and early morning sky.

You can find Comet C/2020 F3 NEOWISE low in the north-western sky after about 11 pm BST when the sky gets dark, and best visible about midnight when the sky is darker. It’s displaying a resplendent tail which sticks up from the horizon, and it should remain visible throughout July, although it will get fainter but higher in the sky. The object remains quite small in the sky, so binoculars will give the best view.

Comet NEOWISE as seen from St Lawrence Bay, Essex, on 18 July at 00:45 BST. Photo: Robin Scagell

This comet is the brightest to be seen from the UK since the brief appearance of Comet McNaught in January 2007. It follows the disappointment of two comets earlier this year which broke up as they neared the Sun.

However, Comet NEOWISE* has survived its perihelion passage, as it was closest to the Sun on 3 July. It is getting closer to Earth, although the predictions are that its brightness will fade as it gets farther from the Sun. Its closest point will be on 23 July, when it will still be over 100 million km from us – so no risk of a collision, if you were wondering!

You can photograph the comet without special equipment, although because it is small phone cameras will not give a good result. Use a good camera on a telephoto setting – around 200 mm on a DSLR camera – and give exposures of no more than a second or two at a fairly high ISO rating. If possible, subsequently stack the separate exposures using software such as Photoshop, Affinity, or the free Deep Sky Stacker program, so as to overcome any ‘noise’ resulting from the high ISO.

Here is a chart showing how the comet’s position changes during July and August, with the horizon for midnight BST. Use the well-known star pattern of the Plough in the north-western sky to judge where to look. The sky moves from left to right during the course of the night, and the comet is at its lowest position in the sky, due north, at 1 am. After that it starts to get higher again with the sky starting to get brighter about 3 am.

The comet is predicted to fade in brightness, and will probably be below naked-eye visibility by the end of July.

Positions for Comet 2020 F3 (NEOWISE) for July and August 2020. The positions are shown for 0h BST on the date shown, so if you are observing just before midnight, use the position for the next day. Map produced using Stellarium.

*Where does the name come from? NEOWISE is a satellite designed to survey the sky in infrared wavelengths. It has discovered thousands of asteroids, many of which are potentially hazardous to Earth, several nearby brown dwarf stars and 28 comets to date.

Comets are named after the discoverer, so each comet has the name NEOWISE. However, the full designation lists the year and week of discovery, so to prevent confusion the full name, in this case C/2020 F3 (NEOWISE) should be used. There was also a C/2019 F3 (NEOWISE), for example, but that was very faint.


Comet NEOWISE, photographed by Paul Sutherland from Walmer, Kent, on 7 July
Photo taken on 10 July at 23:49 BST from Wooburn Moor, Bucks. 2-sec single exposure at ISO 10,000 on Sony A7S camera with 200 mm lens. Photo: Robin Scagell

11-12 July

A view from Barry Linton from Southend-on-Sea on 11 July at 3:30 am BST. He reports the tail as about 2-3 degrees long
A stack of 36 images made using a 66 mm refractor with a Fujifilm X-T10 camera on 11 July. Paul Sutherland observing from Walmer, Kent
11 July at 2 am BST, from Gatemoor Lane, Loudwater, Bucks. Robin Scagell
A display of noctilucent cloud was also visible on the morning of 11 July. Gatemoor Lane, Loudwater, Bucks, 2:55 BST. Robin Scagell
A one-minute pan around the sky on the morning of 11 July showing four planets, the Moon, the comet and the NLC.
Stuart Atkinson’s view includes both meteorological and noctilucent cloud, from Shap, Cumbria
Robert Meardon took this view from Nash, Bucks, on 11 July at 3 am BST.
Photo from Jeff Stevens in North Staffs at 11:31pm 11th July 2020. Canon EOS 1100D at ISO 400, f/7.1 46mm lens, 13 seconds.
Pete Williamson took this photo on 12 July at 12:15 am from Whittington, Shropshire.  Canon 70D with 18-135mm Canon lens at ISO 3200; 4 seconds.
NLC and comet, taken by Jan Wrightson at 3:18 am using Canon 550D, Canon 18-135mm lens, fixed tripod, f5.6, 2 sec, ISO 3200

12-13 July

A tracked shot from Paul Sutherland in Walmer, Kent
Enhanced view of Paul’s photo, so as to reveal the blue gas tail as well as the yellowish dust tail.
From Aston Rowant in Oxfordshire the comet was easily visible around midnight. Photo: Robin Scagell

18 July

This view from St Lawrence Bay, Essex, at 00:46 on 18 July 2020, shows both the white dust tail and the fainter blue gas tail. The dust tail was easily seen with the naked eye, but not the gas tail. Photo: Robin Scagell
By 25-26 July the comet has become much fainter and, while visible with binoculars, is a more difficult object with the naked eye. It is displaying the ‘spring onion’ appearance with a green coma characteristic of smaller and fainter comets. A cropped image from a 200 mm lens shot. Photo: Robin Scagell