Archive for October 15, 2020

10/15/2020 – Ephemeris – The Great Andromeda Galaxy

October 15, 2020 Leave a comment

This is Ephemeris for Thursday, October 15th. Today the Sun will be up for 10 hours and 58 minutes, setting at 6:57, and it will rise tomorrow at 8:00. The Moon, 1 day before new, will rise at 7:30 tomorrow morning.

The closest large galaxy to our Milky Way galaxy is the Great Andromeda Galaxy seen in the eastern sky when it gets dark. It is barely visible to the naked eye. To locate it first find the Great Square of Pegasus high in the east, standing on one corner. The left star of the square is the head of the constellation Andromeda. Follow two stars to the left and a bit downward, then two stars straight up. The galaxy is near that last star as a small smudge of light. Binoculars are the best way to see it as a thin spindle of light. Visually through a telescope one can see only the bright nucleus of the galaxy, that spans six Moon diameters in photographs. M31 is its most famous catalog designation and it is two and a half million light years away.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.


Andromeda and M31 animated finder

Andromeda animated finder, including the Great Andromeda Galaxy. I’ve added Cassiopeia that some folks use to find the galaxy. I start with the leftmost star of the Great Square of Pegasus that connects to Andromeda. I count off two star on the lower curve because they are brighter than the upper curve. Then count two stars up. Next to that top star is a little smudge. That is the core of the Great Andromeda Galaxy. Created using Stellarium and GIMP.

The moon superimposed on M31 for apparent size comparison

The moon superimposed on the Great Andromeda Galaxy, M31, for apparent size comparison. Created using Stellarium and the embedded image of the galaxy with that of the full Moon of October 31, 2020. M31 Image credit: Herm Perez License: “Feel free to use these images, if you use them in a commercial setting please attribute the source.”