Adrian Dening's Stars Over Somerset

Wednesday, 12 January 2022 17:00

Monday 17th to Sunday 23rd January 2022

During the early evening, look high up towards the north east and find the constellations of Cassiopeia (the familiar "W" shape) and Perseus. Between the two constellations is an object known as the Double Cluster. This pair of open clusters was first catalogued as a "patch of light" back in 130BC. They are relatively young, only about 12 million years old and are gradually moving towards us at a speed of approximately 30km/s.

With a magnitude of around +3.8, it will be best to use binoculars or a small telescope. On Monday 17th there is a full Moon, so that will create some light pollution.

While you are looking in that direction, take a moment to identify the star Algol in Perseus. Algol, also known as the "Demon Star", is actually a three-star system and as the stars pass in front of each other, they cause eclipses. This means that the overall magnitude of +2.2 drops to +3.4 every few days when viewed from Earth.

Moving to the evening of Saturday 22nd, there will be an 83%-lit Gibbous Moon and an opportunity to make out the dark lava patches of the Mare Orientale. It is situated right on the western edge of the Moon's nearside, so can be quite difficult to spot. If you imagine the moon as a clock face, Mare Orientale is located at about 8.30, just below the crater Grimaldi. The mare has been likened to a bull's-eye in appearance and along with the usual star charts, I have included an image of Mare Orientale that was taken by NASA's Lunar Orbiter 4 probe in 1967.

Screenshots courtesy of Stellarium
Copyright Adrian Dening and Radio Ninesprings 2022