Adrian Dening's Stars Over Somerset

Wednesday, 11 January 2023 17:00

Monday 16th to Sunday 22nd January 2023

Last week I mentioned the Moon's "libration" or wobble as it orbits around the Earth every 27 days. It means that at certain times, different bits of the surface are tilted a little more towards us.

On Wednesday 18th, the western edge of the Moon is slightly more visible and this is a great chance to spot the Mare Orientale. Mare are large dark basaltic plains and early astronomers thought that they were actually seas, hence the Latin name for them. Mare Orientale resembles a large "bullseye" and it is normally hard to see as it's on the edge between the nearside and darkside of the Moon.

If you're an early riser, at around 6am on 18th, a Crescent Moon will be close to the horizon towards the south east. I have provided a diagram to help you locate the Mare together with a photograph of it that was taken by NASA's Lunar Orbiter 4 probe back in 1967.

If early mornings are not your thing, then you could go outside at 6pm on Sunday 22nd and look towards the south west horizon. Venus and Saturn will appear to be very close together just before they set. Venus will be the lower of the two pinpoints of light.

If you're tempted to use your telescope or binoculars for a better view, please remember not to aim in that direction until the Sun has completely disappeared below the horizon as you must never risk accidentally catching even a brief glimpse of the Sun through them!

Screenshots courtesy of Stellarium
Copyright Adrian Dening and Radio Ninesprings 2023
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