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: -5°C (23°F)
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: 4.5 (can barely see the Milky Way)
Air Temperature: 80°F
Date: June 29, 2019 from 10:30 - 11:30 pm
Location: Backyard, Savannah GA

---

Return to Pat Prokop's Heavenly Backyard Astronomy Page