NGC 6888, the Crescent Nebula (
https://en.wikipedia.org/wiki/Crescent_Nebula), is located in the constellation Cygnus near the bright star Sadr. The emission nebula, also designated Caldwell 27 and Sharpless 105) was discovered in 1792 by William Herschel. Located 5000 light years from Earth, the emission nebula is a product of the impact of shock waves from the stellar wind of red giant HD192163 colliding with the star's ejecta when it became a red giant. The star is likely to go supernova sometime soon (
https://en.wikipedia.org/wiki/WR_136).
Acquisition:
Imaged on 8/1/16 (L) at the Nebraska Star Party at Merritt Resevoir, NE and 8/4/16 (RG) & 8/6/16 (B) from Lake St Louis, MO
Integration: 4 hours (LRGB)
Luminance: 12x600s @ 1x1 (120')
R/G/B: 8/8/8 x 300s @ 2x2 (40'/40'/40')
Equipment
Scope: William Optics GTF 81 5 element refractor (535mm focal length)
Upgraded with Moonlite CF focuser with motor
Imager: QHY9Ms with Olivon OAG and QHYCFW2-s filter wheel
Guidecam: ASI120MM
Filters: Baader LRGB
Mount: Orion Atlas EQ-G
Processing and Software
Guiding with PHD2
Acquisition with Sequence Generator Pro
Integration and processing with PixInsight 1.8
NGC 6888 - The Crescent Nebula:
https://flic.kr/p/KPTYA9Annotated image:
https://flic.kr/p/K3NkLDAstrobin:
http://astrob.in/259107/0/#Space #Astronomy #Astrophotography #Nebula #Stars
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