Rosette Nebula – Ha|OIII Bicolour Composite

The Rosette Nebula processed using the Modified Bicolour technique for combining Ha and OIII images as described by Steve Cannistra – see The bicolour method creates a synthetic green channel (sG) to create a final RGB colour composite Ha:sG:OIII.

Right ascension: 06h 31m 44s | Declination: +05° 08' 49" | Distance: 5,000 Light Years
Field of view: 57 x 38 arcmin

Camera: SBIG ST-10XME
Telescope: William Optics Megrez 120 F/7.5
Guiding: Starlight Xpress Active Optics (SXV-AO-LF) unit
Filters: Baader Ha (7nm), OIII (8.5nm)
Exposures: Ha 26 x 15 min; OIII 48 x 15 min
Total exposure: 18.5 hours
Image composition: Modified Bicolour Ha|sG|OIII composite
Scale: 1.56 arcsec/pixel
Image acquired: January 2012 from Bristol (UK)

Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL (DDP, Fat Tail Deconvolution), Photoshop CS4.