M110 aka NGC205, a wallflower existence in Messier’s catalogue

About the Object

M110, also known as NGC205,  has a certain "wallflower existence" in Messier's famous catalogue. Although it was originally observed by Charles Messier in 1773, it never made it to his catalogue until it was added as its last entry not earlier than 1966! But its negligence didn't stop, as a satellite of the all famous Andromeda galaxy M31, M110 is on countless images also here on astrobin, but hardly ever in the focus. But even worse, when Apple made an image of M31 as their main wall paper in OS Mountain Lion some 15 years ago, M110 was retouched out (like some other gals and star clusters)!

M110 does not deserve such ignorance, it is actually quite an interesting dwarf elliptical, as it has some dust clouds (rarely the case for dwarf ellipticals) and also features a blue core, indicative of some recent star formation.

Observation Notes

While I put the main focus on M110 in this image, I used the proximity to M31 and put M110 a bit off center, so the outskirts of M31 come in as a nice dramatic addition to the image - reminiscent a bit of the famous blue Earth photo of Apollo 8 - M110 "over the ground" of M31. Processing also had its own challenges: I took special care that the outskirts of  M110 and, to lesser extent, also M31 retain a certain "graininess": caused by the proximity and the large but finite number of stars. This implies that one has to take a lighter hand on denoising tools like NXT (in particular the v3 version) and also BXT, as both have a tendency to transform grains into (ugly and unnatural) light worms. Finally, the blue core should also be visible, putting an Sa galaxy as white reference in SPCC helped with that.

Data were taken on 2025 September 19 and 20

Technical Details

View the full-resolution image together with complete acquisition and processing details on AstroBin.