M64 – The Black Eye Galaxy

Click image for full size version

March 4, 2023

M64 is also called the Black Eye Galaxy, the Sleeping Beauty Galaxy, and the Evil Eye Galaxy. It is a spiral galaxy located in the constellation Coma Berenices, about 17 million light years away, and inclined about 60 deg to our line of sight. The inner disk of the galaxy is rotating opposite to the outer regions. It shows a prominent dust lane with lots of details. This galaxy is 53,800 light years across and contains about 100 million stars, possibly due to a galaxy merger long ago. 

Acquisition, focusing, and control of Paramount MX mount with N.I.N.A., TheSkyX; unguided.  Focus with Optec DirectSync motors and controller. Equipment control with PrimaLuce Labs Eagle 4 Pro computer. All pre-processing and processing in PixInsight. Acquired from my SkyShed in Guelph. Good transparency and seeing. Acquired February 11-13, 2023 under a moon-free sky.

Sky-Watcher Esprit 150 f/7 refractor and QHY600M camera with Optolong UV/IR filter
Tak FSQ-106 @ f/5 (530mm), QHY-367C Pro One-shot colour, Optolong UV/IR filter 

109x5m Lum = 9hr05m
114x5m OSC = 9hr35m
Total: 18hr35m
Image scale 0.72 arcsec per pixel 
Finder Chart and Annotated Image: 
Data Reduction and Linear Processing

Preprocessing: The WeightedBatchPreProcessing script was used to perform calibration, cosmetic correction, weighting, registration, local normalization and integration of all frames.

Alignment of Master Frames: DrizzleIntegration was applied to the OSC frames (within WeightedBatchPreProcessing), and the result was aligned to the Luminance master with StarAlignment. This yielded aligned Lum and Colour masters.

Gradient Removal: DynamicBackgroundExtraction was applied to both masters.

Colour Calibration:  ColorCalibration was used to calibrate the OSC master.

Deconvolution: BlurXterminator was used on each master with a custom psf FWHM determined with the PSFImage script, and star sharpening set to 0.10 with “Correct First” selected

Linear Noise Reduction: NoiseXterminator was applied to each image with settings Amount=0.9 and Detail=0.15

Stretching:  HistogramTransformation was applied to each image to make a pleasing yet bright image.

Nonlinear Processing
Luminance addition: LRGBCombination was applied to replace the lightness of the RGB image with the Luminance master.

Star Removal:  StarXterminator was used to remove the stars.

Nonlinear Noise Reduction: NoiseXterminator was used to reduce noise in the background areas of the image with settings Amount=0.9 and Detail=0.1 

Contrast Enhancement: Using a mask to select the galaxy, HDRMultiscaleTransform was applied at scales of 6 and 4, followed by LocalHistogramEqualization three times.  A Contrast Limit of 1.5 and 1 iteration were used for each LHE application (scale 25, strength 0.25; scale 90, strength 0.25; scale 200, strength 0.1).

Sharpening: MultiscaleMedianTransform was used to sharpen Layers 1 – 5 with strengths of 0.03, 0.05, 0.05, 0.04, and 0.03, respectively. 

Star Restoration: Stars removed using StarXterminator were added back into the image using straight addition in PixelMath. 

Final Steps: Background, galaxy and star brightness, contrast and saturation were adjusted in several iterations using CurvesTransformation with masks as required. ICCProfileTransformation (sRGB IEC61966-2.1; Relative Colorimetric with black point compensation) was applied prior to saving as a jpg.