Messier 95 is a barred spiral galaxy located about 33 million light-years away. It was discovered by Pierre Méchain in 1781, and catalogued by Messier four days later.  The galaxy is an intermediate barred spiral, with a ring surrounding the bar.=MsoNormal =MsoNormalExposure: Total exposure time about 14.7 hours, 390:18:19:20 x 2 minutes LRGB. All bin 1x1. Data collected in December 2022.

Light pollution: Bortle 7-8 (white zone, NELM about 4.5)
Seeing: Average FWHM of subs around 2.8 arcsecs
Image scale at capture: 0.6 arcsecs/pixel = f/5.7
Scale of presentation: 0.9 arsecs/pixel

Equipment:
Scope: C11 (standard, not Edge) with Celestron 0.63 reducer
Mount: Paramount MX+, connected via ASCOM Telescope Driver 6.1 for TheSkyX, with MKS 5000 driver 6.0.0.0
Camera: SXVR-H694, connected via SX ASCOM driver 6.2.1.17140 (SX 1.2.2 also installed)
Filter wheel: Atik EFW2 with 7x1.25 carousel and Artemis 2.4.3.0 driver
Filters: Astrodon 5nm Ha/SII, 3nm OIII, Type IIi LRGB
Rotator: Optec Pyxis 2", connected via Andy Galasso's 0.4 driver (Optec Pyxis Rotator AG)
Focuser: Rigel Systems GCUSB nStep motor with driver version 6.0.7 on stock Celestron focuser
OAG: Orion Thin OAG
Guide cam: Lodestar (first generation). 4 second exposures
Automation SW: Sequence Generator Pro 3.0.0.8
Guide SW: PHD2.6.3, connected to guide cam via native SXV driver
ASCOM: ASCOM 6.3.0.2831
Platesolving: PlateSolve 2, failover to local Astrometry.net 0.19 server
Collimation: Metaguide 3, using ASI120MM connected via ZWO Direct Show driver 3.0.0.2
Processing Workflow by Workspace in PixInsight 1.86

1. Processing
Calibration with WeightedBatchPreProcessing with flats and bias, using Cosmetic Correction with a master dark
Blink to preview and manually reject a few frames
Weighting, registration and integration with WBPP
RGB Combination for RGB frames
Dynamic Background Extraction on luminance and RGB images
ImageSolve RGB, then run Spectrophotometric Color Calibration, using Average Spiral Galaxy white reference
BlurXterminator using Correct First on luminance and RGB
NoiseXterminator on luminance and RGB

2. Luminance Stretching
Histo Trans x 3
Curves Trans
Second curves trans, using a mask to bring out the arms without blowing out the core
Mild Localized Histogram Equalization to enhance contrast between arms
I saved images with two different levels of stretching, using one for the bright core and one for the spiral arms

3. RGB Stretching
Create a saturation mask: apply ScreenTransferFunction to Histo Trans, then apply to the stretched luminance image. if needed. Blur the mask slightly with Convolution.
Histo Trans x 2
Curves Trans to boost saturation, using the saturation mask to prevent spurious background colors from being boosted
Curves Trans to brighten

4. Color Blending
LRGB Combine, making separate images for the core and the spiral arms
Mild Multiscale Linear Transform and Localized Histogram Equalization to restore detail in the core
Layer together the core and spiral arms images in Photoshop, using a mask

5. Background Subtraction (Artificial Flat)
Broadband images captured with my (non-Edge) C11 usually had circular artifacts left over from flat calibration, because it’s basically impossible to create accurate flats when the mirror shifts while capturing light frames. To remove these artifacts, I create and subtract an artificial flat, which is simply an image of the messy background, with all stars and imaging targets removed.
a. Create an image of the background by removing stars with StarXterminator
b. Clean this image up in Photoshop, removing any leftover stars
c. Blur this background image slightly (otherwise in the next step you’ll remove all the noise, creating an unnatural-looking noiseless image)
d. Subtract the background from the main image (adding an offset, to avoiding having a pure black background), using a mask to protect the galaxy from being subtracted out

6. Final
Final Histogram Transformation
ICC Profile Transform to sRGB
Rescale to 0.9 arcsecs/pixel
Save as JPG