Astral Imaging at Dogwood Ridge Observatory

Latitude: 3748'51.0" N"
Longitude:7823'41.0"W
Scottsville, Virginia 24590

 

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NGC 6888 The Crescent Nebula

Image Information

From Wikipedia, the free encyclopedia
Crescent Nebula
emission nebula
CrescentBicolorHunterWilson.jpg
Observation data: J2000.0 epoch
Right ascension 20h 12m 7s[1]
Declination +38° 21.3′[1]
Distance 5,000 ly
Apparent magnitude (V) +7.4
Apparent dimensions (V) 18′ × 12′
Constellation Cygnus
Designations NGC 6888,[1] Sharpless105, Caldwell 27
See also: Lists of nebulae

The Crescent Nebula (also known as NGC 6888Caldwell 27Sharpless 105) is an emission nebula in the constellation Cygnus, about 5000 light-years away. It was discovered by Friedrich Wilhelm Herschel in 1792.[2]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 250,000[3] to 400,000[citation needed] 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.

It is a rather faint object located about 2 degrees SW of Sadr. For most telescopes it requires a UHC or OIII filter to see. Under favorable circumstances a telescope as small as 8cm (with filter) can see its nebulosity. Larger telescopes (20cm or more) reveal the crescent or a Euro sign shape which makes some to call it the "Euro sign nebula".

See also[edit]

References[edit]

  1. Jump up to:a b c "SIMBAD Astronomical Database"Results for NGC 6888. Retrieved 2007-04-23.
  2. Jump up^ Erdmann, Robert. "NGC 6888"The NGC/IC Project.
  3. Jump up^ "WR 136".

 

 

 

 

 

 

 

NGC6888 The Crescent Nebula

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3000

NGC6888 The Cresent Nebula

NGC6888 The Crescent Nebula
A Bit Darker

1600D         2000D

3000D

 


 

This image consists of 13 red, 13 green, and 11 blue RGB images all taken at -15C at bin 2x2 for 15 minutes each. A total of 9.25 hours RGB data used. All data was acquired using MaxImDl/CCD version 5.24 using ACP7.1.  Pix Insight version 1.8.02.1098 was used for processing. Dithered guiding was on. Hopefully luminance data will be added soon.

Equipment and Location Information

Date Aug. 15-24, 2014
Location Dogwood Ridge Observatory
Optics Optical Guidance Systems 12.5" RC @f/9
Mount Astro Physics AP1200GTO
Camera SBIG STL-11002M/CW8
Filters Baader LRGB Ha 7nm,SII 8nm, OIII 8.5nm - 50.8mm Unmounted Filters
Conditions Temperature low to mid 50s with moderate to good  seeing. Transparency good to moderate.

   
    
  Last Modified :10/02/12 01:10 PM