Taken on the morning of February 26, 2020 using a Stellarvue SV80ST2 with 0.8X reducer (f/4.8) and a ZWO ASI183MM Pro camera (lowest read noise, ten minutes total integration time, 20 x 30s, for each RGB channel). Guided capture on an A-P Mach1GTO mount.
It was a balmy but somewhat windy morning (Santa Ana conditions) with M3 fairly high in the sky but under red/orange zone light pollution. I have about eight times as many subs to process and run through PixInsight's subframe selector (some from a previous night) so in the end I may end up with about one hour for each channel (after the "bad" subs are thrown out, the seeing conditions weren't very good and for this first pass I just selected the subs sequentially with no quality assessment).
Image capture with Sequence Generator Pro and guiding with PhD v2. Image processing with PixInsight and Photoshop CC2019.
Near the bottom center you can see -- faintly -- NGC 5263, a 14th magnitude spiral galaxy. The bright star toward the lower left is HR 5145 a 6th magnitude, orange-red giant that is nearly twenty-two times the diameter of our sun. The limiting magnitude on this reproduction seems to be somewhere between magnitude 16 and 17 (the faintest stars).
The reproduction scale is 3.8 arc seconds per pixel (capture scale was 1.29) and the median FWHM on the mono-converted, linear RGB master was 6.1 arc seconds (didn't I just say that the seeing were pretty bad?) with a median eccentricity of 0.3 (thus, big and round stars).
Edited by james7ca, 27 February 2020 - 09:46 AM.