Observers in the UK with a clear sky high to the south-southeast shortly after midnight on Sunday, 12 January 2020 can see the 16-day-old waning gibbous Moon just three-quarters of a degree north of the beautiful open star cluster Messier 44, otherwise known as Praesepe, or the Beehive Cluster. AN graphic by Ade Ashford.If you own a pair of binoculars or a small telescope, you may wish to take a look at the Moon on the night of 11–12 January 2020 since it lies in the constellation of Cancer, the Crab. If you look a little more closely, you’ll see that the Moon lies in the same field of view as the glorious open star cluster known as Praesepe, the Beehive Cluster, or more prosaically as Messier 44.
For observers in the British Isles, the Moon’s orbital motion doesn’t bring it closest to the Beehive Cluster until the calendar clicks onto 12 January, by which time the pair are high in the south-southeast. At their closest – 12:30am GMT (00:30 UT) – the 16-day-old waning gibbous Moon lies just three-quarters of a degree north of the heart of Praesepe. In a telescope, use your lowest magnification eyepiece and watch as the Moon glides over the northern edge of M44, occulting (passing in front of) a number of its fainter stars.
A scholarly investigation of the Cairo Calendar papyrus (1244–1163 B.C.) has led researchers at the University of Helsinki to conclude that the ancient Egyptians were aware that the variable star Algol (beta Persei) had a 2.85-day period. Given that the star’s current period is 2.8673 days, this supports the theory that mass transfer between the stars of this eclipsing binary has caused a long-term increase of its orbital period.
On Sunday, 29 March around civil dusk, observers throughout the British Isles with suitably steadied binoculars and small telescopes can watch naked-eye star Epsilon (ε) Tauri disappear behind the darkened hemisphere of the almost 5-day-old waxing crescent Moon, reappearing again slightly more than an hour later. Here’s our where and when guide to viewing it.
UK observers with a clear sky an hour before sunrise on Friday 28 October should look very low in the east-southeast to see the slim crescent of the 27-day-old Moon less than four lunar diameters away from largest planet Jupiter. The Moon and Jupiter are also joined by third-magnitude double star gamma (γ) Virginis, commonly known as Porrima.
