M95 and M96

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November 20, 2022

M95 (left) and M96 are prominent spiral galaxies in Leo, with both appearing a similar size. M95 is around 32 million light years distant. M96 is 35 million light years from us. Both are part of the Leo I group of galaxies, which contains between 8 and 24 galaxies. If you look carefully you’ll see numerous other galaxies in this field, but they are much, much further away.

Tekkies:
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. Average transparency and seeing. Acquired January 29 – March 3, 2022, mostly 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 

 
49x10m Lum = 8hr10m
122x5m OSC = 10hr10m
Total: 18hr20m
Image scale 0.72 arcsec per pixel 
 
Finder chart and Annotated Image: 
   
 
Data Reduction and Cleanup

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

DrizzleIntegration was applied to the OSC frames, and the result was aligned to the Luminance master with StarAlignment. This yielded aligned Lum and Colour masters.

DynamicBackgroundExtraction was applied to the luminance and OSC masters.

ColorCalibration was used to calibrate the OSC master.

Colour 

Linear Noise Reduction: NoiseXterminator was used to reduce noise in the background areas with settings Amount=0.9 and Detail=0.25 

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

Luminance
Deconvolution: A stretched clone of the Lum image was used to make a mask selecting bright regions of the galaxy for deconvolution. Deconvolution was applied (30 iterations, regularized Richardson-Lucy, ParametricPSF mode with default settings; Global dark deringing = 0.002; Global bright deringing 0.0007).

Linear Noise Reduction: NoiseXterminator was used to reduce noise in the background areas with settings Amount=0.9 and Detail=0.25 

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

Combining Luminance and Colour Images
Luminance addition: LRGBCombination was applied to replace the lightness of the RGB image with the Luminance master.

Additional Processing
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=0.25 

Contrast Enhancement: LocalHistogramEqualization was applied using an inverted lightness mask to protect the background and select the galaxy. Four passes were applied, each with 1 iteration at max contrast of 1.5 (scale 20, strength 0.25; scale 50, strength 0.25; scale 100, strength 0.22; and scale 150, strength 0.18).

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.