NGC 4631 - The Whale Galaxy

Lum - 30 x 15 minute subs (no binning, -25c)
R - 9 x 10 minute subs (2x2 binning, -25c)
G - 9 x 10 minute subs (2x2 binning, -25c)
B - 9 x 10 minute subs (2x2 binning, -25c)

Total exposure is 720 minutes or 12 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 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. Final tweaks including 180 degree rotation in Photoshop.

Image Credit: Steve Mastellotto and Paul Mortfield