Friday, November 20, 2015

M32 and M110, Andromeda's satellite galaxies

Andromeda Galaxy, the most distant object visible to the naked eye is often one of the most viewed DSOs by amateur astronomers. It lies about 1 arc degree from the star nu Andromedae (35 And), a spectroscopic binary that is bright enough to be seen with the naked eye in a fairly dark sky. All of the above make Andromeda Galaxy, one of the easiest objects to locate in the sky. However, the same cannot be said about its companions the dwarf galaxies M32 and M110.

One of the main problems to see both objects is Andromeda itself. Its brightness takes all the attention and overshadows both galactic satellites.

With an apparent magnitude of 8.1, a surface brightness of 12.46 and an angular size of 8.5' x 6.5', M32 is the easiest to see. Apparently, it seems to make a right scalene triangle with two stars of 9th magnitude and in the binoculars it looked like a stellar, but fuzzy object of similar magnitude to its two companions stars. I had seen it from a Bortle 9 sky and there had been no clue that it wasn´t a non-stellar object.

On the other side of Andromeda lies M110. It has an apparent magnitude of 8.1, similar to M32 and a surface brightness of 13.98 because its angular size (19.5' x 11.5') is much larger than M32. I tried to hunt M110 in various sessions, but I only managed to see it from my Bortle 5 sky in a night with excellent transparent and good seeing.  Despite being less affected by Andromeda’s glance than M32 that practically lies in the outskirts of the giant galaxy, M110 is a galaxy very tough to see (at least from my skies). It looked like a ghostly patch and I could only perceive it with averted vision after full dark eye adaptation.

I wish to the readers a dark and clear sky and that the next time you take a look at Andromeda, you can see these 3 magnificent galaxies.


Edited by Jennifer Steinberg (editor in chief)

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