And XXX reprocess

[wimvb]

Recently I've reprocessed a few of my older images with the new tools in PixInsight, and I was able to get more faint detail to show. Now the turn has come to one of my deepest images, that of dwarf satellite galaxy Andromeda XXX (And XXX, Cass II). This galaxy was discovered in 2012 by analysing stars in the vicinity of ngc 147 and ngc 185. A total of 8 (!) stars were used in that study to identify the galaxy. The three galaxies ngc 185, ngc 147 and And XXX are located a few hundred thousand light years in front of M31, just over 2 million light years from the Milky Way. Back in 2022 when I collected and processed the data, I could just about identify the stars used in the study. That by itself is somewhat of a feat. Clearly, with a modest amateur telescope (the SkyWatcher Maksutov Newtonian MN190) it's possible to resolve single stars that are over 2 million light years away. This time I used BlurXTerminator to sharpen the stars just a little more. StarXTerminator also did a better job at isolating stars from background galaxies than my previous method. This time I could keep quite a few of the very distant faint background galaxies. I used the annotation tool in PixInsight with custom catalogues to identify hundreds of these background galaxies, up to more than 1.5 billion light years distant. There are even more unidentified galaxies in the final image.

The large version (click on it to expand). The bright star  in the lower left corner is 7 mag HD 3574

The annotated version (click on it to expand). Each white cross is a background galaxy. Red crosses are stars in And XXX

The inverted Luminance, cropped and annotated. All 8 stars are resolved.

Technical details:

Telescope SW MN190 with ZWO ASI294MM camera

Exposures:

RGB 5 hours in total, 300 s at gain 0

L 25 hours in total, 180 s at gain 0

[Oscar23]

Fantastic rich-field image, wimvb. I didn't know about this dwarf galaxy before. I'm amazed they can even tell it's there.

Only one problem - running a search of "Andromeda XXX" to learn more returns much saucier results than desired!

[Xilman]

Very nice!  You have prompted me to have a go when the galaxy is well placed.

Not at all surprised to see you image and identify individual stars at that distance, AE And and AF And, which are variable stars in M31, are in my regular observing program. With care they can be found in images taken with telescopes as small as 80mm aperture.

 

[wimvb]

1 hour ago, Oscar23 said:

Only one problem - running a search of "Andromeda XXX" to learn more returns much saucier results than desired!

Forgot to warn you. I did so in my original post, but that was two years ago.

"(Btw, don't Google Andromeda XXX without parental guidance 😉 )"

I followed up on that post after I had collected more data.

 

 

[wimvb]

4 minutes ago, Xilman said:

With care they can be found in images taken with telescopes as small as 80mm aperture.

Wow, I thought that that would require a very large dob.

[wimvb]

1 hour ago, Oscar23 said:

Fantastic rich-field image, wimvb. I didn't know about this dwarf galaxy before. I'm amazed they can even tell it's there.

Only one problem - running a search of "Andromeda XXX" to learn more returns much saucier results than desired!

When I read about it before imaging, I expected it to be a faint fuzz on my subs, something like a very faint ngc 147, or one of our own galaxy's dwarfs.

Btw, search for andromeda satellite galaxies on wikipedia if you want to limit your search to astronomical targets.

Edited Thursday at 09:37 by wimvb