M4

M4 (NGC 6121) is a Shapley-Sawyer class IX (http://en.wikipedia.org/wiki/Shapley%E2%80%93Sawyer_Concentration_Class) globular cluster located approximately 7,200 light-years away in Scorpius. It is easy to find in the sky because it is just over a degree away from the bright (magnitude ~1) star Antares.

Luminance – 12x300s – 60 minutes – binned 1x1
Luminance – 4x600s – 40s minutes – binned 1x1
RGB – 13:12:13x300s – 65:60:65 minutes each – binned 1x1
RGB – 4x600s – 40 minutes each – binned 1x1

490 minutes total exposure – 8 hours 10 minutes

Imaged over eight nights in May, June, July and September, 2021 and May, 2022 at the El Sauce Observatory (Rio Hurtado, Chile) with a FLI PL 9000 on a PlaneWave CDK24 at f/6.5 3974 mm.

This data is from Telescope Live (https://telescope.live/) “One-click Observations.”

LRGB - https://www.flickr.com/photos/dcrowson/53152808132/sizes/l/