Hipparchus (lower left) and adjacent Albategnius are ancient lunar impact craters. North on the Moon is to the left in this picture. Image credit: Marnix PraetHipparchus and Albategnius are a photogenic pair of ancient impact craters lying in the lunar central highlands just to the east of Mare Nubium. Hipparchus is much degraded and modified, due to multiple impacts that have occurred since its formation in the same impact that formed Mare Imbrium some three to four billion years ago. Hipparchus is 160 kilometres (100 miles) wide. Albategnius is a slightly smaller (136 kilometres) but magnificent walled-plain, its walls having huge peaks rising in places 3000-4250 metres (10-14000 feet) above the plain. Its central peak is 1200 metres (4000 feet) high. The smaller craters lying between the two are Halley (centre) and Hind (top), with Klein jutting into Albategniusʼ south-western (lower right) rim. The best time to observe and image the pair is at First and Last Quarter. This nice image was taken by Marnix Praet from Belgium with a ten-inch (250mm) Newtonian fitted with a 3x Televue barlow and a DMK21 camera.
Observers up for an extreme observing challenge may care to make an attempt at viewing the almost full Moon pass in front of planet Neptune soon after 8pm BST on Thursday, 15 September. The planet’s disappearance occurs at a low altitude in twilight for the British Isles, but can also be seen from a large swathe of Europe and western Russia.
What’s the youngest Moon you’ve ever seen? While the best opportunities generally occur in Northern Hemisphere spring when the ecliptic’s high, 21st January offers UK observers a 28-hour-old lunar crescent.
