A comet discovered just a few weeks ago looks set to become a bright object towards the end of May, although it will be at its brightest in a twilit, rather than dark, sky. Here is how to see it.
It is called Comet Swan, because it was discovered on March 25 using the SWAN camera, which usually observes the solar wind, on the SOHO spacecraft. The comet has the official label C/2020 F8.
At the start of May, the comet had already reached fifth magnitude, and there are hopes it could become as bright as magnitude 3 or better later in the month. It could therefore make up for the disappointment at the break-up of Comet Atlas (C/2019 Y4), which had promised to become bright around the same time.
Comet Swan has been too far south to be seen so far from northern latitudes, but southerly observers have taken photos showing a round condensed head and a fine and growing gas tail, making it resemble a spring onion.
Related: Our guide to comets
Over the next three weeks, it heads rapidly north, passing through the constellations of Cetus, Pisces, Aries, Triangulum and Perseus. At the start of June, it will lie in Auriga, close to Capella, one of the brightest stars in the sky. The comet will be at perihelion, when it is closest to the Sun, on May 27.
When at its best, in Perseus and Auriga, the comet will actually be circumpolar from many northern locations, including northern USA and Canada, northern Europe, the UK and Ireland. This means it will remain above the horizon all night, though it will be easier to spot in the late evening or pre-dawn twilight, when it will be a little higher in the sky.
You will definitely need a good horizon, unobstructed by hills and buildings, and clear of low cloud. Look to the north-west horizon as the sky darkens after sunset, to see if you can spot the comet, using our chart as a reference to show you where it is. Likewise, if you are observing in the morning before dawn, start looking an hour or more before sunrise, before twilight becomes too bright.
Binoculars will certainly help you see the comet. Ideal size for hand-holding would be 10×50 or similar, where 10 is the magnifying power, and 50 is the width of each front lens in millimetres. You can find suitable binoculars from reputable makes, such as Celestron, Olympus and Orion, at Amazon. Here is a link to a choice of binoculars for readers in the USA, and here is a link to such binoculars if you want to buy in the UK.
If the comet becomes as bright as is hoped, and keeps a good tail, it will also make a great target for photographers. Take a range of exposures at different settings to find which best captures it. Fortunately today’s digital cameras allow us to see results immediately, revealing which settings work best.
Here is our guide to what else you can see in the sky this month.
