Messier 81 is a spiral galaxy about 12 million light-years away in the constellation Ursa Major. Due to its proximity to Earth, large size and active galactic nucleus (which harbors a supermassive black hole), Messier 81 has been studied extensively by professional astronomers.
The galaxy's large size and relatively high brightness also make it a popular target for amateur astronomers.
Data captured 27th & 28th December, 2017.
19x 3 minute exposures with Blue filter.
29x 2 minute exposures with Green filter.
17x 3 minute exposures with Red filter.
117x 1 minute exposures with Luminance filter.
This was the first image captured with my Atik 428EX CCD camera. The target certainly required much more data but the weather & the full moon would not allow me any more data for at least another 2 weeks so I decided to process the data I had.
Skywatcher Quattro 200 CF
Atik 428EX Mono
This image was processed in Pixinsight & Lightroom.
Calibration and Stacking in Pixinsight using Batch PreProcessing
Dynamic Crop - To remove black edges & integration artifacts. (Each Channel)
Dynamic Background Extraction - To remove gradients. (Each Channel)
Deconvolution - To bring out some fine detail & tighten stars, 50 iterations. (Each Channel)
Multiscale Linear Transform - Noise reduction. (Each Channel)
Histogram Transformation - To stretch the image
ChannelCombination - To combine RGB channels.
Photometric Colour Calibration - To calibrate colours.
SCNR - To remove green cast.
LRGB Combination - To blend my luminance image with my RGB image.
TVGDenoise - Some additional noise reduction, rangemask in place.
HDR Multiscale Transform - To recover some detail in the galaxie's core.
UnsharpMask - To sharpen with mask in place to exclude stars & background.
Curves Transformation - To boost contrast.
Dark Structure Enhance - To boost detail in dark areas.
Curves Transformation - To boost saturation.
Histogram Transformation - Clip Blacks.
Histogram Transformation - Clip Blacks with mask in place to protect galaxy.
Curves Transformation - Increase Saturation with previous mask inverted to protect background & stars.
Export as JPEG and import into Lightroom.
Contrast Boost (+15)
Clip Blacks (-25)
Increase Vibrance (+15)
Export final JPEG for upload.