Celestial hemisphere:  Northern  ·  Constellation: Coma Berenices (Com)  ·  Contains:  IC 3946  ·  IC 3947  ·  IC 3949  ·  IC 3955  ·  IC 3959  ·  IC 3963  ·  IC 3973  ·  IC 3976  ·  IC 4040  ·  IC 4042  ·  IC 4045  ·  IC 4051  ·  IC 4106  ·  IC 4111  ·  NGC 4860  ·  NGC 4864  ·  NGC 4865  ·  NGC 4867  ·  NGC 4869  ·  NGC 4871  ·  NGC 4872  ·  NGC 4873  ·  NGC 4874  ·  NGC 4883  ·  NGC 4886  ·  NGC 4889  ·  NGC 4895  ·  NGC 4898  ·  NGC 4906  ·  NGC 4907  ·  And 8 more.
Getting plate-solving status, please wait...
The Coma Cluster, 


The Coma Cluster
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The Coma Cluster

Getting plate-solving status, please wait...
The Coma Cluster, 


The Coma Cluster
Powered byPixInsight

The Coma Cluster

Acquisition details

May 3, 2021 ·  May 5, 2021 ·  May 7, 2021 ·  May 9, 2021
Astrodon 50 mm G: 24×900(6h) -20°C bin 1×1
Astrodon 50mm B: 24×900(6h) -20°C bin 1×1
Astrodon 50mm L: 48×900(12h) -20°C bin 1×1
Astrodon 50mm R: 24×900(6h) -20°C bin 1×1
Flat darks:
Avg. Moon age:
24.68 days
Avg. Moon phase:
Mean SQM:
Mean FWHM:

RA center: 13h00m59s.0

DEC center: +27°5837

Pixel scale: 0.468 arcsec/pixel

Orientation: 179.010 degrees

Field radius: 0.555 degrees

Resolution: 7574x3914

File size: 5.2 MB

Locations: KG Observatory, Julian, CA, United States

Data source: Backyard


Five years ago I made my first attempt at this amazing cluster using a Celestron 8" in an urban 19.5 SQM sky...

Coma Cluster using Celestron 8" in 19.5 SQM sky

For my revisit 5 years later using a 24" in a 21.3+ SQM sky, I was very fortunate to have 8 consecutive nights of clear, dark and steady skies with seeing between 1.6" and 2.3" for Luminance and 1.4" to 2.9" for RGB.

This is a 2-panel LRGB mosaic with 6:3:3:3 hours per panel for a total of 30 exposure hours.

For the merge, I used PI GradientMergeMosaic after StarAlignment Register/Union - Seperate. DBE was used on frames prior to and after the merge to help smooth gradients.

Framing was a little tricky to avoid cutting into any significant galaxies. The glow at the lower left is from a cropped-out bright star, similar to the one above, that was uncomfortably close to the frame edge.

It's interesting to note that the full extent of this cluster was not understood until it was more thoroughly studied in the 1950s by astronomers at Mount Palomar Observatory, only a few miles away from this location.

"The Coma Cluster is a large cluster of galaxies that contains over 1,000 identified galaxies. Along with the Leo Cluster, it is one of the two major clusters comprising the Coma Supercluster. It is located in and takes its name from the constellation Coma Berenices.

The cluster's mean distance from Earth is 321 million light years. The central region is dominated by two supergiant elliptical galaxies: NGC 4874 and NGC 4889. Most of the galaxies that inhabit the central portion of the Coma Cluster are ellipticals. Both dwarf and giant ellipticals are found in abundance in the Coma Cluster.

About 90% of the mass of the Coma cluster is believed to be in the form of dark matter."


Sky plot

Sky plot


The Coma Cluster, 



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Unique or Unusal Deep Sky Targets