Observers in the UK with a view low to the west about 1am BST on Saturday, 11 May 2019 (some 1½ hours before moonset for the centre of the British Isles) can see the 6-day-old waxing crescent Moon just 1½ degrees from the prominent open cluster Messier 44, otherwise known as Praesepe, or the Beehive Cluster. After the Moon has set in Western Europe its orbital motion brings it even closer to M44, actually occulting some of the cluster’s southernmost stars as seen from North America’s Eastern Seaboard just before local midnight on on 10 May. AN graphic by Ade Ashford.The Moon was new on 4 May, so the young lunar crescent soon makes its presence known at dusk, particularly in Northern Hemisphere skies where the ecliptic makes a steeper angle to the western horizon. If you own a pair of binoculars, you may wish to take a look at the Moon on the night of 10-11 May since it lies in the constellation of Cancer, the Crab, in the same field of view as the beautiful open star cluster known as Praesepe, the Beehive Cluster, or more prosaically as Messier 44.
For observers in Western Europe and the UK, the Moon’s orbital motion doesn’t bring it close to the Beehive Cluster until the calendar clicks onto 11 May, by which time the pair are well on their way to setting in the western sky. For anyone in the British Isles the last views will be around 1am BST on Saturday 11 May when the 6-day-old Moon lies just 1½ degrees from the heart of Praesepe and the duo will be just 10 degrees – about the span of a fist at arm’s length – above the west-northwest horizon.
This conjunction of Praesepe and the Moon favours the Eastern Seaboard of North America where, as night falls on Friday, 10 May the lunar crescent is poised to pass in front of the western edge of the star cluster. If you have a telescope, use your lowest magnification eyepiece and watch from 10pm local time until midnight as the Moon glides over the southern edge of the Beehive Cluster, occulting (passing in front of) a number of its stars.
If clear skies persist, observers in the UK can view four naked-eye planets between now and the end of the month. Brightest planet Venus is visible low in the west some 45 minutes after sunset, while the waxing Moon is your celestial pointer to Jupiter, Saturn and Mars between 21 and 28 July at midnight.
On Wednesday 18 January, brightest asteroid 4 Vesta comes to opposition in the constellation of Cancer bordering on Gemini, ideally placed for observation by Northern Hemisphere skywatchers. While the truly eagle-eyed among you might glimpse it with the unaided eye on dark, moonless nights, Vesta is an easy binocular object.
On Saturday 27 August at 22:32 UT (11:32pm BST), a spectacularly close conjunction occurs between Jupiter and Venus just 22 degrees west of the Sun in the constellation of Virgo, when the planetary pair are just 4 arcminutes, or one-fifteenth of a degree, apart. Here is our guide to the best locations and times to view this rare event.
