The Crescent Nebula (NGC 6888 or Caldwell 27) is an emission nebula in the Cygnus constellation, about 5000 light years away. It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (HD 192163) colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 400,000 years ago. The result of the collision is a shell and two shock waves, one moving outward and one moving inward. The inward moving shock wave heats the stellar wind to X-ray emitting temperatures.

Photo Details

  Telescope: Sky90@4.5 405mm

  Camera: Asi1600MMC-pro, Filter wheel, ZWO 36mm LRGBHSO filters

  Mount: NJP Takahashi

  Guiding: Off-axis

  Exposure: H 36x5min OIII 36x5min

  When: April 2018

  Other information: My first bi-color



Photo Details

  Telescope: Celestron C8N (1000mm)

  Camera: Sbig ST-2000XM, Filter wheel, Baader 1.25" LRGB filtes

  Mount: NJP Takahashi

  Guiding: Self-guided

  Exposure: HRGB 7h

  When: ---

  Other information: my first HA with this newton




Other links