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The Crescent Nebula by Dave Collings

Submitted by Chelsea Chin

NGC6888: “The Crescent Nebula”


  • Plane Wave Instruments 12.5” CDK telescope with the PW 0.63 reducer on the Astro-Physics 1100 GTO CP4 mount.
  • Main camera is the ATIK 16200 Mono with Chroma filters for HA, OIII, and SII.
  • Imaged in narrowband HOO for 8 hours total with 4 hours of Ha and 4 hours of OIII.
  • Stacked as a bi-color image with Ha to Red, OIII to Green, and Blue with some pixel math allowing some Ha to the Blue channel.


“NGC6888 is an emission nebula in the constellation Cygnus, about 5000 light-years away from Earth.  NGC6888 has an apparent magnitude of 7.4.  It is formed by the fast stellar wind from the Wolf-Rayet star (WR 136)  colliding with and energizing the slower-moving wind ejected by the star when it became a red giant star.  The result of the collision is a shell and two shock waves, one moving outward and one moving inward revealing the beautiful OIII and Ha of the Crescent.

Being 3000 ft up in the Blue Ridge Mountains allows for very dark skies yielding good details of deep space objects.”

David Collings – Blue Ridge Observatory | Sparta, North Carolina  USA