Barnard 33 - the Horsehead Nebula
Ha - 28 x 30 minute subs (no binning, -25c), used all 28 subs
Lum - 28 x 15 minute subs (no binning, -25c) used 22 subs
R - 14 x 10 minute subs (2x2 binning, -25c) used 11 subs
G - 14 x 10 minute subs (2x2 binning, -25c) used 11 subs
B - 14 x 10 minute subs (2x2 binning, -25c) used 11 subs
Total exposure is 1500 minutes or 25 hours. The data was captured with a 16-inch f/8.9 RCOS on a Paramount ME, SBIG STL11000M CCD with Astrodon LRGB filters, field flattener located at the Sierra Remote Observatories outside of Fresno, California at 4600 feet elevation.
All image calibration (Lights, Bias, Darks and Flats) and processing was done in PixInsight. RGB files used Dynamic Background Extraction, Photometric Colour Calibration, ArcSinH stretch followed by mild Histogram Transform stretch, HDR Transform, Noise Reduction (ACDNR). Luminosity and Ha used Dynamic Background Extraction, ArcSinH stretch followed by mild Histogram Transform stretch, HDR Multiscale Transform and Noise Reduction (ACDNR). LRGB was then created from processed RGB and Lum data and Ha added using the Narrowband Combination script. Final tweaks in Photoshop.
Image Credit: Steve Mastellotto and Paul Mortfield