Monthly Archives: September 2014

Crescent Nebula (NGC6888) – First Light Anser Observatory

NGC6888-bicolour-v1lceThe Crescent nebula is an emission nebula in the constellation of Cygnus about 5000 light-years away.  It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (the bright star at the centre of the nebula) colliding with and energising the slower moving wind ejected by the star when it became a red giant around 250,000 – 400,000 years ago. The shock waves from this collision can be seen in the image.  This image was created by combining emission-line images in Hydrogen-alpha and Oxygen [O III] using the Modified Bicolour Narrowband Technique developed by Steve Cannistra.

This is a double first light image.  It is the first published image from the Anser Observatory – my relocated observatory situated in the Polden Hills of Somerset.  It is also the first light image from my new APM 152-1200ED APO Refractor.

Right ascension: 20h 12m 07s | Declination: +38° 19′ 41″ | Distance: 5,000 Light Years
Field of view: 54 x 37 arcmin
Camera: SBIG ST-10XME
Telescope: APM 152-1200ED F/6.2 with Riccardi x0.75 Reducer
Guiding: Off-axis with Lodestar guider
Filters: Astrodon Ha (3nm), OIII (3nm)
Exposures: Ha 19 x 20 min, OIII 36 x 20 min
Total exposure: 18.3 hours
Image composition: Cannistra Modified Bicolour Narrowband Technique
Scale: 1.49 arcsec/pixel
Image acquired: May – July 2014

Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL; Photoshop CS4; Focus Magic