The Great Globular Cluster in Hercules (Messier 13)



The Great Hercules Globular Cluster (Messier 13)
The globular is located about 25,100 light-years from Earth. It is estimated to contain about 300,000 stars. Most of these stars are about 11.65 billion years old, as compared to our sun which is relativity young star at 4.6 billion years. I took this image on the night of Monday, August 27, 2018 in my backyard. Exposure time (for the image) was 40 minutes. The cluster is high overhead at 9 pm on this date.

Techy Stuff:
Telescope: 11" Celestron Edge HD with 0.7x Reducer Lens converting the focus ratio at f/7
Camera: Canon T7i (modified for astrophotography)
Capture software: Backyard EOS v3.1.16 Premium Edition
Guiding: PHD 2 (RMS error: 0.72 ... i.e. good tracking)
Mount: CGEM ii
Light Frames: 20 at 120 seconds with ISO setting 800
Dark Frames: 20 at 120 seconds with ISO setting 800
Bias Frames: 10
Filter: Baader UHC-S
Stacked in PixInsight
Post Processed in Photoshop CC
Seeing Conditions: 7 (0-10, where 0 is total cloud cover)
Bortle Light-Pollution zone: 7 (can barely see the Milkyway)
Temperature: 78F, Dew Point 72
Location: Backyard, Savannah GA


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