NGC 2264 describes several objects in the constellation Monoceros lying about 2,700 light-years from Earth. One is the Christmas Tree star cluster nearby the blazing bright blue star S Monocerotis at centre right. The surrounding diffuse nebula is caused by H-alpha emissions from hydrogen gas stimulated by ultraviolet radiation emitted by S Monocertis and the cluster’s other blue stars. The nebula is well known for two special star forming regions. At centre left is the Cone Nebula named for its apparent shape and sculpted by fierce stellar winds. It is a dark molecular cloud within which other new stars are forming. Numerous other sculpted swirls of nebulosity are nearby. At lower right is the Fox Fur Nebula (Sharpless 273) named after its rich textured appearance also the result of sculpting by stellar winds. In contrast, the blue reflection nebula is caused by scattered blue light reflecting off residual dust in a region where stars have already formed.
This image is a bicolour combination of Ha and OIII images to create a synthetic green image displayed as an RGB composite with Ha luminance. PixInsight DBE (Dynamic Background Extraction) was used in the absence of suitable flat frames to remove sky background noise and gradients. Photoshop CC layers and layer mask processing techniques were used for colour and spatial enhancement – Levels, Curves, Reduce Noise, Selective Color, HDR toning, Smart Sharpen, Local Contrast Enhancement and Unsharp Mask in predominant use. Additional noise reduction (TGVDenoise) and local contrast enhancement (HDRMultiscaleTransform) was carried out in PixInsight.
Right ascension: 06h 41m 08s | Declination: +09° 41′ 15″ | Distance: 2,700 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 8 x 20 min, OIII 11 x 20 min
Total exposure: 6.3 hours
Image composition: Cannistra Modified Bicolour Narrowband Technique
Scale: 1.49 arcsec/pixel
Image acquired: 8th, 9th & 16th February 2015
Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL; Photoshop CC, PixInsight