Playing with the Revised Bologna Catalogue

[coatesg]

I took a series of images of part of M31 early one evening last month while waiting for the target I wanted to rise above a tree. With 70min of exposures (as 14x5m), I have a quick image of the SW region of the galaxy (including NGC206) as below. I'm kinda looking to progress this further over time and it's potentially the first phases of a mosaic project - needs much more exposure, and colour, I reckon about 4 frames might cover it... but this is something for next season now. 

For fun, and while waiting for better weather, I've grabbed a copy of the Revised Bologna Catalogue (http://cdsarc.u-strasbg.fr/viz-bin/Cat?cat=V%2F143&target=brief&) from VizieR and sorted it to include only the confirmed globular clusters. By outputting this in tab separated format, it's possible to use this within the Annotate script after a platesolve in Pixinsight to highlight what we have (or havent) got...

Here's the quickly processed version (reduced in PI and processed TGV, Masked Stretch, Histogram Stretch, HDRMT and LHE and then Morphological Transform via a Star Mask to reduce the stars a little), and followed by an inverted (and slightly darkened) version with annotated display of the catalogue entries. There are about 170 globulars plotted here (there are 600 + in the catalogue as a whole) with the RBC identifier and quoted V magnitude in brackets - there's a couple of PGC galaxies there too 

Cheers

EDIT: 

Should have added image details - all on FLT110 at ~ f5.7 with WO FR, ST2000XM @ -20C, Lum filter. All on Losmandy Titan.

[Knight of Clear Skies]

Nice work, the annotations add interest. I wonder how the globs were identified originally as they look very much like stars, spectroscopically or by some other method?

[coatesg]

31 minutes ago, Knight of Clear Skies said:

Nice work, the annotations add interest. I wonder how the globs were identified originally as they look very much like stars, spectroscopically or by some other method?

Cheers. I think a combination of spectroscopic analysis, and high resolution imaging for classification. The catalogue is in 5th revision - details: http://www.bo.astro.it/M31/ . The 600+ items include candidate items, as well as some that turned out to be stars, galaxies, HII regions, etc. There's a flag in the dataset to indicate what it was (and in some cases, this is specific to the source of the data that has been combined into the RBC).