The Great Globular Cluster in Hercules (M13)

• Telescope: Stellarvue SVA130T-IS
• Mount: Losmandy G-11 with Gemini 2 controller
• Autoguiding: Yes (sub-arcsecond rms accuracy)
• Optical Configuration: 2x Barlow lens (f/14)
• Camera: Canon 60Da
• Light Frames: 5, 5-min. and 5, 3-min. exposures stacked
• Calibration: 12 dark frames (no flats, no biases)
• Exposure Time: 40 min. (5 x 5 min. + 5 x 3 min.)
• ISO: 800
• Processing: Photoshop CC
• Imaging Location: Sierra Nevada Mountains (Altitude: 8,600 ft.)

Like most globular clusters, The Great Globular Cluster in Hercules (M13) is one of the oldest structures in the universe–about 12.7 billion years old. Astronomers believe that  globular clusters formed very soon after the Big Bang. In fact, these star formations pose something of a dilemma for cosmologists, because the universe itself is thought to be about 13.7 billion years old and some globular clusters seem to be even older than that.

Located in the constellation Hercules, M13 is 25,000 light-years from Earth and contains about 300,000 stars.