Globular Cluster in Scorpius ... Messier 4



Globular Cluster in the constellation of Scorpius ... Messier 4
M4 is a rather bright cluster visible to the naked eye under ideal seeing conditions. The reason why it is bright and large is simply due to distance. At only 7,200 light-years away, it is one of the closest globular clusters to our Solar System. The cluster is about 12.2 million years old and contains a bit more than 20,000 young and old stars. Perhaps it has gone through a couple of cycles of stellar formation. It is best viewed in the early summer where it is medium high in the south at midnight at my latitude of 32 N.

Techy Stuff:
Telescope: 11" Celestron Edge HD at f/10
Camera: Altair Hypercam 294c Pro TEC
Sensor Temperature: -5C (23F)
Filter: City Light Pollution Suppression
Capture software: #SharpCap Pro V 3.2
Guiding: PHD 2 (RMS error: 0.25 ... i.e. very good tracking
Mount: CGX
Mount controls: Celestron PWI V2.1.25
Polar Alignment: QHY Pole Master
Light Frames used: 54 at 60 seconds / Gain: 25,000
Binning: 1x1
Dark Frames: 30
Bias Frames: 30
Flat Frames: 30
Stacked in Deep Sky Stacker
Post Processed in PixInsight and Photoshop CC
Seeing Conditions: 6 (0-10, where 0 is total cloud cover)
Moon: No Lunar Interference
Bortle Light-Pollution zone: 6.5 (can barely see the Milky Way)
Air Temperature: 80F
Date: June 29, 2019 from 10:30 - 11:30 pm
Location: Backyard, Savannah GA


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