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!
Mercury attains a greatest easterly elongation of 19 degrees from the Sun on 1 April. This solar separation combined with a favourable inclination of the ecliptic to the western horizon an hour after sunset, means that the period 25 March to around 8 April offers the year’s best evening showing of the innermost planet for Northern Hemisphere observers.
Comet 41P/Tuttle–Giacobini–Kresák orbits the Sun every 5.4 years and will pass through perihelion (its closest point to the Sun) on 12 April 2017. Motoring through Ursa Major at close to 2°/day during the remainder of March, this fascinating comet with a history of dramatic surges in brightness, passes close to Messier 97 and 108 on the UK night of 22 March.
Jupiter is now less than a month from opposition (7 April), so it’s very much open season for the Solar System’s largest planet. If you’re unsure where to find it, the rising 17-day-old waning gibbous Moon passes just two degrees from Jupiter on the UK evening of 14 March. Virgo’s brightest star, first-magnitude Spica, makes it a great binocular triumvirate.
On the night of 4-5 March 2017, UK observers with clear skies can see an occultation bonanza as the 6-day-old waxing crescent Moon passes in front of prominent members of the Hyades open cluster in Taurus. Some hours later, after the Moon has set in the British Isles, first-magnitude star Aldebaran is occulted across a large swathe of North America.
Currently setting over four hours after the Sun as seen from the heart of the UK and visible in the west-southwest at dusk, dazzling Venus is about to hit peak brightness in the constellation of Pisces. The planet attains magnitude -4.8 on Friday 17 February — some 21 times the luminosity of brightest star Sirius gracing the southeast horizon as darkness falls.
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.
Dazzling Venus and much fainter Mars have a close encounter with a young Moon in the constellation of Pisces at UK dusk on Tuesday 31 January. The trio form an equilateral triangle small enough to be encompassed by the field of view of a 7x binocular low in the west-southwest for a couple of hours from 7pm GMT.
Before sunrise on Thursday 19 January, observers in Western Europe can see an interesting celestial conjunction in the southern sky. At about 6am local time, the waning gibbous Moon, largest planet Jupiter and Spica — the brightest star in the constellation of Virgo — all lie in a line encompassed by the field of view of a typical 7x or 8x binocular.