TheSkySearchers

M4 (NGC 6121) is a Shapley-Sawyer class XI (http://en.wikipedia.org/wiki/Shapley%E2 ... tion_Class) globular cluster located approximately 6,500 light-years away in Scorpius.

Luminance – 24x600s – 240 minutes – binned 1x1
RGB – 8x300s – 40 minutes each – binned 2x2

360 minutes total exposure – 6 hours

Imaged May 1st, 2020 and May 4th, 5th and 6th, 2021 from Dark Sky New Mexico at Rancho Hidalgo (Animas, New Mexico) with a SBIG STF-8300M on an Astro-Tech AT12RCT at f/8 2432mm.

LRGB - https://www.flickr.com/photos/dcrowson/ ... 0/sizes/l/

My wider, refractor image is here - https://www.flickr.com/photos/dcrowson/26627906420/.



Dan

10-minute Luminance exposures? Wow!

My ZWo1600mm at 0 gain would be blown out on my Luminance filter at 5 minutes.

Nice. M4 is a real bear for me to see visually from home, as in I'm lucky to detect a small, very faint blotch.