The open star cluster M103 as taken Friday morning under Bortle 7 skies. I lost about 25% of my subs to intermittent high clouds and I ended up with about 36 minutes of total integration time. The faintest recorded stars seem to be just short of magnitude 19 but it's hard to know exactly since this image goes deeper than my common references (ASTAP catalog or WikiSky.org). WikiSky shows fainter stars in their DSS2 All Sky Survey but they don't label/identify many stars once you reach mid-18 magnitude.
Image capture was with N.I.N.A with processing in PixInsight and Photoshop 2024. Click on the preview to see at full size (1600 x 938 pixels) and to read all of the capture details that are in the captions. North is oriented up and the reproduced image scale is approximately 1.3 arc seconds per pixel (the original capture scale was 0.52 arc seconds per pixel).
[UPDATE]
I did a dump of PixInsight's Gaia data base down to magnitude 20 and compared that to a few coordinates for the faintest stars in my image and I found a very faint hint of a few stars that were at magnitude 19, but the stars that are clearly recorded seem to be a few tenths under 18.5. I also used ASTAP to measure the limiting magnitude and it returned a magnitude of 19 using all of its defaults. So my estimate remains somewhere between 18.5 and 19.
[/UPDATE]
Attached Thumbnails
Edited by james7ca, 07 September 2024 - 11:26 AM.
