My first serious effort on a galaxy with the AP155. What a telescope. What an object! Really happy with the detail I managed to capture in NGC 604.
Constructive comments welcomed.
Ed Beshore
Acquisition Details:Observed on 9/19/2022 9/24/2022 10/28/2022 10/29/2022 10/31/2022 11/1/2022 12/17/2022
Filter: R : Exposure time: 2h 50m 00s (10200.0 seconds in 65 exposures)
Filter: G : Exposure time: 4h 02m 00s (14520.0 seconds in 83 exposures)
Filter: B : Exposure time: 4h 06m 00s (14760.0 seconds in 83 exposures)
Filter: H-Alpha : Exposure time: 3h 08m 00s (11280.0 seconds in 62 exposures)
Filter: L : Exposure time: 3h 58m 00s (14280.0 seconds in 82 exposures)
Total object exposure time is 65040.0 seconds, (18h 04m 00s) in 375 exposures
Workflow DetailsRaw Images- Calibration used nightly sky flats and pushed through Pixinsight's weighted batch preprocessing
- All images were either 120 sec or 240 sec integrations.
- All masters were cropped using Dynamic Crop
RGB- Linear fit of three channels using Red channel (lowest signal) as the reference
- RGB combine
- Dynamic Background Extraction
- Spectrophotometric Color Calibration
- Blur Exterminator (default settings)
- Noise Exterminator (default settings)
- Generalized Hyperbolic Stretch, including linear stretch to raise the black point a bit
- Star Exterminator to copy properly colored stars for later integration into HaLRGB Combination with unscreened checkbox
Luminance- Dynamic Background Extraction
- Blur Exterminator (default settings)
- Noise Exterminator (default settings)
- Generalized Hyperbolic Stretch, including linear stretch to raise the black point a bit
LRGB Combination- RGB Working space to equalize the color channels in the RGB Image
- Channel Extraction to isolate the L from the RGB Image
- Linear Fit to set the extracted L image to the same level as the actual luminance data
- Channel Combination to restore extracted L to RGB
- LRGB combination to create a new RGB image with the RGB + L data
- Curves transformation to slightly reduce the redness in the spiral arms and bring out the blue
H-Alpha- Pixelmath to boost the levels to avoid small-number roundoff
- Blue Exterminator (default settings)
- Noise Exterminator (default settings)
- Star Exterminator to remove stars
- Generalized Hyperbolic Stretch
- Pixel math to create a RGB Color H-Alpha using
- R = 0.93 * H-Alpha
- G = 0
- B = -.07 * H-Alpha
HaLRGB Combination- Prepare an elliptical softened mask with GAME script from Hartmutt Bornemann to cover core of galaxy and protect it from HA addition
- Applied Mask to LRGB Combined Image
- PixelMath to combine H-Alpha Image to LRGB Image HA*0.25 + LRGB*0.75
- Curves Transformation to reduce redness from the Pixelmath
- Generalized hyperbolic stretch to raise levels overall
- Removed mask
- Star exterminator to remove improperly colored stars
- Pixelmath to perform screened combination of starless HALRGB with stars from RGB image
- BlueExterminator to only sharpen stars (no non-stellar sharpening)
- Local histogram equalization with amount of ~50% amount to bring out dust lanes and improve equalization in the core of the galaxy and isolate the spiral arms a bit
Ta daaa! 
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