StormEffects

Nightscapes & Deep Sky Colors

Astrophotography Brian A. Morganti


NGC 6888 - Crescent Nebula

Cygnus

50%  resolution view of Crescent Nebula area below

NGC 6888, also known as the Crescent Nebula, is a cosmic bubble about 25 light-years across, blown by winds from its central, bright, massive star.  When this star, WR 136, became a red supergiant around 400,000 years ago, it ejected huge amounts of gas.  Today, WR 136 is energizing the gas, producing a fast stellar wind which forms the so called Crescent Nebula in the Cygnus constellation.  The star is shedding its outer envelope in a strong stellar wind, ejecting the equivalent of the Sun's mass every 10,000 years. The nebula's complex structures are likely the result of this strong wind interacting with material ejected in an earlier phase. Burning fuel at a prodigious rate and near the end of its stellar life this star should ultimately go out with a bang in a spectacular supernova explosion.

This emission nebula, at a distance of about 5000 light years from Earth, depicts two shock waves, one moving outward and one moving inward.  Oxygen atoms produce the blue-green hue that seems to enshroud the detailed folds and filaments.

IMAGE DETAILS:

  • Date & Location:  September  5/6, 2013  - StarEffects Observatory, Bernville, PA

  • Weather:  Calm, Average temperature of 52F

  • Sky Conditions:  Mostly clear with above average transparency. 

  • SQM-L:  20:34 start - 20:68 end.

  • Optics:  TeleVue NP101is Refractor w/TeleVue Focal Reducer = 432mm @ f4.3

  • Filter:  CLS-CCD Astronomic DSLR clip in  (Light Pollution Suppression)

  • Mount:  AP900GTO

  • Guiding:  Orion SSAG @ 5 second exposures w/TeleVue TV60is

  • Camera:  Canon T1i (500D) Hap Griffin Modified - Baader UV/IR

  • Exposure:  243 min (27 x 9minute subs = 4hrs-5min total) @ ISO 800 RAW using Custom White Balance

  • Calibration Frames:  12-10min Darks, 12 Bias, 12 Field Flats w/Alnitak Flat Man - All Custom White Balance

  • Processing:  Images Plus 4.50b, PS CS6, NIK filters

  • Comments:  This is a target I had never attempted to image before, perhaps thinking it may not be all that different than a lot of other emission nebula.  Obviously I was wrong!  The Crescent Nebula offers a lot of interesting and intricate details and stands out beautifully against a backdrop of expansive red emission nebula!

 

Astrophotography  -  Nightscapes & Deep Sky Colors

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