Another redo of a 2021 image, with the new 120mm refractor.

M65 M66 NGC 3628 - The Leo Triplet

In addition to the new scope, and twice the integration time, I did two new techniques for processing. First, I removed the stars very early on, so I could focus on the galaxies without wrecking the stars. (Thanks, StarXTerminator!) Second, I created rough oval and rectangular masks so I could process each of the three galaxies independently, bringing out the best in each. 


Preprocessing
1. WeightedBatchProcessing
2. Create preview around galaxies (avoids DynamicCrop later, and speeds Drizzle)
3. DrizzleIntegration with Region of Interest that crops to preview
4. Dynamic Background Extraction on all filters

Ha (used for M66 only)
1. StarXTerminator on linear images, discarding stars
2. EZ Decon (I had to be tricky here, taking a PSF from the L image with stars, and a “star mask” of a completely black image)
3. EZ Denoise
4. Histogram Transformation to stretch image

L
1. StarXTerminator on linear image, discarding stars
2. EZ Decon (I had to be tricky here, taking a PSF from the L image with stars, and a “star mask” of a completely black image)
3. EZ Denoise
4. Histogram Transformation to stretch image
5. Export to TIFF, import to Photoshop, and create 3 rough masks (ovals & rectangle) for the three galaxies to allow separate processing: mask_M65, mask_M66, mask_NGC3628.
6. For each galaxy, one by one to allow individual adjustments,  do the following:
-a. Create Range Selection for bright galaxy core.
-b. PixelMath “mask_M66 + range_mask”
-c. Apply this mask to L
-d. Histogram Transformation to darken bright galaxy core
-e. Apply galaxy mask
-f. LocalHistogramEqualization with kernel radius ~40 and amount ~40% 
-g. Histogram Transformation to brighten galaxy a bit more

RGB
1. ChannelCombination
2. ImageSolver script
3. Photometric Color Calibration
4. HistogramTransformation to stretch SLIGHTLY so stars are the size I want (but galaxies are still too dim)
5. StarXTerminator to move stars to a new image, leaving galaxies on their own image
6. EZ Soft Stretch
7. Convolution to 3.0 StdDev
8. LRGB Combination to apply L, with 0.3 saturation
9. Repeat LRGB Combination, with Color Noise Reduction
10. Apply M66 mask, then use PixelMath “R: .4*Ha + .8*$T; G: $T; B: $T” to add Ha highlights
11. CurvesTransformation on each galaxy, using those galaxy masks to color-adjust each one independently
12. Add RGB_stars back, with PixelMath “1-((1-RGB)*(1-RGB_stars))”
13. HistogramTransformation on RGB_stars to make them bigger and brighter
14. Export both RGB (galaxies & stars) and RGB_stars to TIFF
15. Open both “BigStars” and “SmallStars” in Photoshop, with SmallStars on the top layer
16. Use erase tool to “punch out” some stars to expose the larger, non-reduced stars in the background (this gives a slight 3D effect)