Waid Observatory

Object: NGC 6888
Date: Aug. 03-08-26-28, 2014   -   Location: Starr-Waid Observatory, Davis Mountains, TX
Telescope: ATRC10  -  Camera: Apogee ALTA U8300  -  Mount: Paramount MX
Guided using Innovations Foresight On Axis Guider (ONAG)
Exposure: HA 330 min. OIII 150 min. RGB 50 min. each
Filters: Astrodon 5nm HA - 3nm OIII - RGB
Image Credit: Preston Starr and Donald Waid

Click on the image to view at higher resolution.

  NGC 6888 - The Crescent Nebula


NGC 6888 (The Crescent Nebula) 1

NGC 6888 is located approximately 4,700 light years from Earth and is known as the Crescent Nebula because of its distinctive shape.  Technically it is classified as a Wolf-Rayet nebula.  Such a nebula is formed when a very hot, massive star ejects its outer layers in a strong stellar wind.  In the case of the Crescent Nebula the star responsible (WR 136) is the bright star in the center of the image above.  As the star ages it begins to shrink and grow much hotter.  Its stellar wind becomes more rarefied but much faster.  This fast stellar wind then collides with the older ejected gas and pushes it into a relative dense bubble.  WR 136 is in the final stages of its stellar life and is estimated to explode in a supernova event within the next million years.  The image above was captured using HA and OIII filters.  The image was assembled by mapping HA to red, OIII to blue and green, and RGB to the stars.


Copyright Donald P. Waid