Comet C/2019 Y4 was discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) on 28 December last year and brightened 6000-fold in just two months to attain magnitude +7.5 on 1 April. Alas, the comet’s nucleus has now fragmented, dashing hopes for a conspicuous naked-eye spectacle in the constellation of Perseus. Here’s our telescopic observing guide.
Grab your binoculars to catch a glimpse of speedy Comet C/2018 Y1 Iwamoto over the coming week before the glare from a full Moon on 19 February drowns it out. Potentially attaining magnitude +6, the comet passes closest to Earth on 12 February when it can be found traversing Leo at a rate of 7.2 degrees/day. Don’t miss C/2018 Y1’s close enounter with galaxy NGC 2903 on 13 February – by eye, camera, or live online.
Bright Comet 46P/Wirtanen skims past Earth just 30 lunar distances away on 16 December when it could become a diffuse magnitude +3 object almost a degree wide located between the Pleiades and Aldebaran in the constellation of Taurus. Grab your binoculars and find a dark sky location well away from streetlights to enjoy this Christmas comet before the glow from a waxing Moon gets too bright from 17 December.
Despite the glow of a waxing Moon, early April is a good time to catch a glimpse of comets 41P/Tuttle–Giacobini–Kresák and C/2015 V2 (Johnson) that are currently circumpolar and visible throughout the UK hours of darkness. And if you’re an early riser, there’s seventh-magnitude C/2017 E4 (Lovejoy) low in the pre-dawn eastern sky too!
Comet 45P/Honda–Mrkos–Pajdušáková passes just 0.08318 astronomical units (7.73 million miles, or ~32 lunar distances) from Earth on the morning of 11 February. Early risers can catch the magnitude +7 comet speeding through the constellations of Hercules, Corona Borealis (CrB) and Boötes at up to 9 degrees/day.
Amateur and professional astronomers are invited to provide observations of comets 41P/Tuttle-Giacobini-Kresák, 45P/Honda-Mrkos-Pajdušáková, and 46P/Wirtanen that will pass by Earth at distances ranging from 0.08 to 0.15 astronomical units. Such close approaches of a trio of comets within the next two years are rare and typically occur only once every few decades.