Globular cluster M33-U49

[Xilman]

Just to prove that globular clusters in external galaxies are quite easy to image, here is U49 in the Triangulum Galaxy M33. It is magnitude V=16.3 and so well within range of a 3" / 80mm telescope.  There are a number of other globular clusters in this image which are easy find if you're interested. Just ask if you would like a catalogue of their positions.

 

 

Image taken 2020-11-07 but only just processed.

0.4m Dilworth

Unfiltered Starlight Xpress 814 CCD camera

1230 seconds (i.e. 20.5 minutes) exposure in 41 x 30 second subs).

 

 

Edited October 6, 2023 by Xilman
Correct magnitude.

[Paul M]

I'm a recipient of your Globs list Paul but have had little chance to use it. But your image above got me thinking...

I imaged M33 about a year ago but lost the stacked FITS file in a spectacularly successful but entirely unintended wiping of my imaging drive in January. However, I did post a JPEG of that image and I've found it in my attachments list on the forum. It's not the best image but ASTAP did plate solve it, which allowed my to do some annotating of some of the globs on this list: 

 https://www.researchgate.net/figure/M33-GLOBULAR-CLUSTER-TARGET-LIST_tbl1_230984922

The last one one the list is within the confines of my image but seemingly too faint. Any others on the list but not annotated are outside the the frame.

I'm quite chuffed, and as always, thanks for posting your off-the beaten-track images.

[Xilman]

Paul: could you mail me your plate-solved version of the above image please? I would like to see what else of interest it may contain.

A major point of my "off-the-beaten-track" postings is to prompt others into extending their horizons and to push their capabilities as hard as they can.  Anyone can, and does, take pretty pictures. Anyone who wants to stand out from the crowd needs to try harder than the rest.

[Paul M]

Hi Paul, only just spotted your response.

Here is the image again but solved and saved as a FITS file, so that should have the solution in the header, I think?

1226034964_M332022-12-1455x60LEQMODHEQ56ZWOASI071MCPro_stacked.thumb.jpg.5a05d24a9e152b902a09306b3412634a.fits

While playing I also found R14 but I didn't annotate it. The yellow box in the attached image is not related to anything I just managed to pollute the JPG image with some clutter.

[Xilman]

Thanks Paul.  It does indeed have a WCS.

One of the things I intend to look for is Y Tri, a variable which I intend to add to my program.

Paul (the other one)

[Xilman]

Congratulations.  You have picked up an individual star in an external galaxy. It is a blue supergiant variable known as Y Tri. I haven't had chance to measure its brightness with any accuracy but guess it is around 18th magnitude. It is fainter than any of the comparisons on the AAVSO chart but I'm pretty sure it is measurable and will report back.

 

[Paul M]

2 hours ago, Xilman said:

Congratulations.  You have picked up an individual star in an external galaxy.

Wow! Who'd have thunk it!

What a nuisance it is to lose the original subs. There would likely have been useful photometry data there. ASTAP did photometrically calibrate this image but it can't separate the object from the background to derive a spot magnitude. I did use the tool that measures total magnitude within a selection box and that returned 17.9

One last trick from ASTAP is to annotate SIMBAD objects within a selected area, and not that I doubted your identification, but it conformed the fix!