NGC6888 - Crescent Nebula - OSC + Mono Luminance (Jonathan W MacCollum)

NGC6888 - Crescent Nebula - OSC + Mono Luminance

After a number of false starts with this target I finally have acquired sufficient data to take a stab at processing the Crescent Nebula. I spent seven different nights trying to image it, but ended up rulling out the first 4 nights when I discovered much better data was being acquired when my primary mirror was being heated up. The dew seemed to have formed a very thin layer on the nights where data was acquired early in the morning and the sharpness and contrast in the last few nights were leaps and bounds better.

The color data was provided by the asi071mc pro camera (0.97"/px) and bayer drizzled with 0.7 drop shrink and luminance data was provided by the asi183mm pro camera (0.5"/px.)

D1 - 224x120s with 071mc pro OSC (7.5 Hours)

D1 - 60x120s with 183mm pro Mono (2 hours)

Processing steps:

Luminance Data:

* Drizzle 60x2min D1 data with drop shrink of 0.7

* DBE to create L_Orig

* Deconvolution with regularization and no local support

* TGV and MMT Noise Reduction of L_Orig

* Use Starnet++ to create a star mask, and expand, convolve it until a mask sufficient for fixing ringing in the deconvolution image can be made

* Replace the ringing stars in deconvolution with L_Orig

* Combine Deconvolution and Noise Reduction image with a clipped / convolved luminance mask (high signal deconvolution and low signal noise reduction)

* Stretch with Masked Stretch

Color Data:

* CFA Drizzle 224x2min OSC data with drop shrink of 0.7

* Register with luminance for cropping/alignment

* DBE, Background Neutralization and Photometric Color Calibration

* TGV and MMT Noise Reduction

* HSV Repaired Separation

* Stretch with Histogram Stretch

* Shrink Stars with contours based mask and morphological transformation

* Desaturate the extra blue haze from the center-most bright star

Combine L+OSC with LRGB Combination

Adjust curves for contrast and saturation

Original
Final
B

B

Description: Fix bad edge caused by dithering

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Status	Advanced success
Started	...
Astrometry.net job	2769953
PixInsight job	5JVSX8NUP7C61CEUATFFCKYANBBGL4SD
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	20h11m54s.650
RA (top/left)	20h13m43s.606
RA (top/right)	20h09m54s.305
RA (bottom/right)	20h10m05s.329
RA (bottom/left)	20h13m53s.138

Dec (center)	+38°23′10″.63
Dec (top/left)	+38°39′34″.72
Dec (top/right)	+38°36′34″.84
Dec (bottom/right)	+38°06′41″.10
Dec (bottom/left)	+38°09′39″.39

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