Because the Moon takes the same time to rotate on its axis as it does to orbit around us, we always see the same face and are never able to see what is called the "dark side". However, our natural satellite exhibits something called "libration" which means it wobbles a bit and sometimes we can see a bit further around the surface than at other times.
A couple of weeks ago I mentioned the seas or "mare" on the lunar surface and the obvious Sea of Tranquility where Apollo 11 landed. The Mare Orientale on the western limb of the Moon is much harder to spot, but on Saturday 25th, the Moon's libration tilts Mare Orientale and a crater near it called Grimaldi into a slightly more favourable position. You will need to be up early though, to catch what will be a crescent Moon, rising above the south east horizon from 6am.
There are a number of excellent early evening opportunities to spot the International Space Station next week. Monday 20th at 5.46pm, Tuesday 21st at 6.34pm, Wednesday 22nd at 5.45pm, Thursday 23rd at 6.33pm and Friday 24th at 5.45pm. At least one of those evenings has got to be clear surely! You are looking for a bright pinpoint of light that appears towards the west and spends up to six minutes passing silently overhead, before disappearing to the east.
Finally, a reminder that my next astronomy talk and star party at the Ham Hill Visitor Centre is scheduled for 7pm on Friday 31st January. To reserve places, please contact the Ham Hill Ranger's Office direct on 07973 887129.
www.starsoversomerset.com
Screenshots courtesy of Stellarium
Copyright Adrian Dening and Radio Ninesprings 2025
Two new litter-pick stations have been installed, equipped with litter pickers and reusable bags for anyone to borrow and do their own two-minute clean-up at countryside sites across South Somerset.