Messier 13 The Great Globular Cluster in Hercules

Messier 13 The Great Globular Cluster in Hercules

Can you believe that there might be several hundred thousand stars, even up to a million in this tiny part of the sky?

M13, also known as The Great Globular Cluster in Hercules, is usually the most identifiable Messier object. This is a very tight cluster first observed by Edmond Halley and cataloged by Charles Messier. Under perfect seeing conditions in dark skies, the cluster can ben barely seen with the naked eye. However, with binocular or any telescope, the fuzzy patch is unmistakable. With telescopes that are larger than 8” inches, one can start resolving individual stars. At most star parties, anyone with a large scope of over 12 inches will use M13 to show off the scope’s resolution power. At Cherry Springs Star Party in 2015, I observed M13 through a 36” telescope. I was able to visually resolve some of the stars at the core of M13.

In 1974 we were somehow able to encode a bunch of data about us, humans, like the DNA, what we look like along with Earth’s position in the universe, and sent off this data from the Arecibo Observatory radio telescope towards M13 in an attempt to contact potential extraterrestrial civilizations. Experts wonder whether this was a good idea or not since a globular cluster seems like an unlikely region to detect life. The gravitational pull of all the nearby stars makes it unlikely for there to be a stable planetary orbit that can host a planet that is friendly towards life.

Processing Info

This was a relatively easy target to capture and edit. This was only two 5-minute subs stacked along with 10 darks and 10 bias frames. I used M13 to test out autofocus while the clouds were over NGC6888 (The Crescent Nebula).

The following processes were performed in PixInsight:

  • Dynamic Crop
  • Dynamic Background Extraction
  • Automatic Background Extraction
  • Background Neutralization
  • Photometric Color Calibration
  • Histogram Transformation
  • Curves Transformation

Once I found what I liked, I saved the files, went to Photoshop, and ran Topaz AI DeNoise. This is an amazing plugin that works like magic.

If anyone is curious, here are the full-res versions of the images.

The area of the sky in HerculesHere you can see the area of the sky in Hercules imaged.

Acquisition Data

  • Telescope: Explore Scientific ED127 Air-Spaced Triplet Apochromatic Refractor
  • Camera: ASI071MC Pro
  • Guide Scope: Orion ST80
  • Guide Camera: ASI290MM Mini. Dithering every image at 1 pixel each time.
  • Mount: iOptron CEM60
  • Software: Image acquisition using N.I.N.A. PixInsight for stacking and editing, Photoshop for final editing along with Topaz DeNoiseAI for noise reduction.
  • Other Accessories: AstroZap Dew Heater, Explore Scientific 2″ Field Flattener, ZWO EAF motorized focuser.
  • Filters: Optolong L-Pro 2″
  • Exposure Time: 10 minutes (2 X 300 seconds). Gain 90, -10°C bin 1×1
  • Exposure Start: 22:17
  • Location: Glassboro, NJ, United States
  • GPS Coordinates: Lat. 39.702774° N, Long. -75.11195° E
  • Temperature: 65°F/18.3°C
  • Bortle Dark-Sky Scale: 5
  • Astrometry.net job: 3626441
  • Avg. Moon age: 22.35 Days
  • Avg. Moon phase: 47.81%
  • RA center: 16h 41′ 41.980″
  • DEC center: +36° 27′ 19.965″
  • Orientation: 227.919 degrees
  • Field radius: 0.672 degrees
  • Magnitude: 5.8
  • Resolution: 3720 x 2330