Skywatch line for November 6 and 7th, 2024 written by Alan French
The Sun rises at 6:36 A.M. on Wednesday and sets at 4:41 P.M. On Thursday it rises at 6:38 and sets at 4:40. This Thursday has just under 17 and a half minutes less daylight than last Thursday.
The Moon was new last Friday and is now moving toward first quarter. A waxing crescent Moon is now in the sky, rising after the Sun and becoming easily visible as darkness falls. At 5:30 P.M. on Wednesday a 26% sunlit Moon sits 16 degrees above the south southwestern horizon. It sets at 8:16 P.M. By Thursday at 5:30 P.M. the Moon’s visible face is 36% in sunlight and it lies 21 degrees above the horizon and farther toward the south. It sets at 9:26 P.M. The Moon will reach first quarter this coming Saturday.
By 9:30 P.M. the Moon has set on both nights, and the most distant celestial sight easily visible to the unaided eye will be almost at the zenith. Under dark skies, free of light pollution, a faint, oblong, cloud is visible high in the south, just shy of overhead. To see it best, give your eyes 20 to 30 minutes to get used to the dark. Your pupil opens wider almost immediately, letting in more light, but that is a modest improvement. It takes time for a chemical, rhodopsin, also known as visual purple, to build up and greatly increases your eye’s sensitivity to light, allowing you to see celestial sights better.
This faint cloud, appearing larger than the Moon, is the Andromeda Galaxy, which contains roughly one trillion stars. It lies 2.5 million light years away from us, so the light you saw traveled for 2.5 million years before it reached your eyes. It is known to amateur astronomers as M31, being the 31st object on French astronomer Charles Messier’s list of 110 celestial objects.
Although best seen under dark skies, M31 is visible where there is some light pollution. If you live where there is moderate light pollution and cannot see it, or are just having trouble spotting the galaxy, binoculars should bring it into view.
If you have trouble is locating it, you can find it from the Great Square of Pegasus. High toward the south southwest is a large square of stars. The upper left star is Alpheratz. Although originally belonging to Pegasus and still part of the Great Square, it is officially in the constellation Andromeda. Counting it as one, count upward along the lower chain of stars going left and upward three stars. Counting the third star as one, then count upward and right three stars. The Andromeda Galaxy lies just above the third star.
If you are out around 9:30 P.M., look for brilliant Jupiter at magnitude -2.7, 31 degrees above the eastern horizon. Fainter Saturn, magnitude +0.9, will be 33 degrees high toward the southwest.