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.
In the remaining days of October and early into November, a fascinating series of planetary peregrinations plays out low in the East before dawn twilight gets too bright. Venus, like a sprinter on the inside lane of a running track, overtakes both Jupiter in Mars in two readily observable conjunctions set against the stellar backdrop of constellations Leo and Virgo.
While antipodean observers are enjoying views of the totally eclipsed Blue Moon in Cancer the Crab on the night of 31 January/1 February, Northern Hemisphere observers should look out for magnitude +6.9 1 Ceres at opposition in the northern fringes of the same constellation. The dwarf planet puts on a good show in the dark of the Moon during February.
As dusk fades to dark on Saturday, 11 June, observers in the British Isles should look low in the western sky to see the 7-day-old waxing crescent Moon and Jupiter less than 3 degrees apart, within the same binocular field of view. Get your observations in now as the solar system’s largest planet is poised to leave the celestial stage during the summer.
