Despite the glow of a waxing Moon, early April is a good time to catch a glimpse of two interesting comets that are currently circumpolar from the British Isles, meaning that they are sufficiently close to the North Celestial Pole such that they neither rise or set, visible throughout the hours of darkness.

Comet 41P/Tuttle–Giacobini–Kresák, a periodic comet that orbits the Sun every 5.4 years, is predicted to fade from magnitude +6.7 to +7.6 during the month. Comet 41P passes just 0.6 degrees north of Thuban, otherwise known as alpha (α) Draconis, at 2am BST on 3 April. By 11 April, 41P lies between eta (η) and theta (θ) Draconis; then the comet passes just 0.6 degrees from beta (β) Draconis – the magnitude +2.8 star known as Rastaban in the head of the celestial dragon – eight days later. Comet 41P crosses the border into neighbouring Hercules on 20 April, a constellation where another bright comet resides this month. C/2015 V2 (Johnson) is a hyperbolic comet destined to leave the Solar System but predicted to brighten a full magnitude to +7.4 by the end of April. C/2015 V2 lies between naked-eye stars tau (τ) and upsilon (υ) Herculis at 12am BST on 22 April, and between the latter and phi (φ) Herculis on 25 April. There’s also a bright comet in the morning sky. C/2017 E4 (Lovejoy) was discovered by Australian comet hunter Terry Lovejoy last month and is currently a seventh-magnitude object in eastern Pegasus, currently some 7 degrees northeast of magnitude +2.4 star epsilon (ε) Pegasi, otherwise known as Enif. C/2017 E4 (Lovejoy) presently rises in the east-northeast around 3am BST from the British Isles.

Inside the magazine

For a comprehensive guide to observing all that is happening in the current month’s sky, tailored to Western Europe and North America, obtain a copy of the April 2017 edition of Astronomy Now.

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