Comet 41P/Tuttle–Giacobini–Kresák in the constellation of Draco was about magnitude +6.5 on the night of 1-2 April when captured in this three-minute integration with a colour Starlight Xpress Ultrastar camera at the f/2 HyperStar focus of the author’s Celestron C11 Schmidt-Cassegrain telescope. AN image by Ade Ashford.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.Comets 41P/Tuttle–Giacobini–Kresák in Draco and C/2015 V2 (Johnson) in Hercules are very well placed for Northern Hemisphere observers during April — particularly in the dark of the Moon. Click on the graphic for a detailed PDF finder chart suitable for printing and use outside at the telescope. AN graphic and finder chart by Ade Ashford.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.Displaying more of a tail than Comet 41P, C/2015 V2 (Johnson) in the constellation of Hercules was about magnitude +8 on the night of 1-2 April when captured in this seven-minute integration with a colour Starlight Xpress Ultrastar camera at the f/2 HyperStar focus of the author’s Celestron C11 Schmidt-Cassegrain telescope. AN image by Ade Ashford.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.
While 2014 was the year the Rosetta spacecraft celebrated making it into orbit around a comet, 2015 was the year it got down to some serious hard work. Its comet, with the tongue-twisting name 67P/Churyumov–Gerasimenko, made its closest approach (186 million kilometres) to the Sun, a period known as perihelion when the comet would be expected to be at its most active. Rosetta was there to witness this.
Comet 252P/LINEAR will zip past Earth on Monday, 21 March at a range of about 3.3 million miles. The following day, comet P/2016 BA14 will safely fly by our planet at a distance of about 2.2 million miles, or nine times the distance to the Moon. This will be the second closest flyby of a comet in recorded history next to comet D/1770 L1 (Lexell) in 1770.
NASA scientists are tracking the upcoming Halloween flyby of asteroid 2015 TB145 with several optical observatories and the radar capabilities of the agency’s Deep Space Network at Goldstone, California. Only discovered sixteen days ago, the 400-metre-wide asteroid will fly past Earth at a safe distance slightly farther than the Moon’s orbit on 31 October at 5:05pm GMT.
