Jones 1 in Pegasus

Jones 1 (PN G104.2-29.6) is a highly evolved, magnitude 15.1 planetary nebula located about 2500 light years away. The nebula is roughly spherical, with an angular diameter of 5.5 arcminutes, but I’ve found no explanation for the odd structure of the nebula, with the divergent bright regions on either side. The nearby Ha region seems likely to be part of the nebula, but I’ve found no discussion of that either. The nebula was discovered by Rebecca Jones at Harvard in 1941.

Exposure: Total exposure time about 20 hours. 26:27 x 20 minutes OIII:Ha, 20:20:20 x 2 minutes RGB. All bin 1x1. Captured September-October 2020.
Light pollution: SQM ~18.38 (Bortle 7-8, NELM at zenith about 4.5, Red/white zone border.)
Image scale at capture: 0.6 arcsecs/pixel = f/5.7
Scale of presentation: 1.2 arcsecs/pixel (50% original size)

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 Type IIe 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 3.1.0.457
Guide SW: PHD 2.6.7, 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 1.8.8:

1. Calibration
Calibration with WeightedBatchPreProcessing with flats and bias, using Cosmetic Correction with a master dark
Blink to preview and reject a few frames
Weighting and registration with WBPP

2. Stack and Mure Denoise
Image Integration on each channel
Mure Denoise on each channel
RGB Combination for RGB frames
Dynamic Background Extraction
Dynamic Crop

3. Narrowband Linear Processing
No deconvolution or other sharpening on these images

4. Narrowband Stretching
Histo Trans x 2
Curves Trans
TGV Denoise

5. RGB Linear Processing
Photometric Color Calibration, using Average Spiral Galaxy white reference

6. RGB Stretching
Histo Trans
Curves
Boost color saturation with additional Curves
TGVDenoise

7. Colorization
Narrowband luminance: PixelMath: max(OIII, Ha)
Narrowband color:
PixelMath, mapping Ha:OIII:(85% OIII + 15% Ha) to R:G:B
Color Mask to select cyan regions, then stretch with Histo Trans and blur with Convolution
Shift cyan to blue with CurvesTrans
LRGB to merge narrowband luminance and color
Mild Localized Histogram Equalization, with a Range Mask, to enhance nebula structure
Port narrowband and RGB starfield images into Photoshop for blending

8. Photoshop
Remove embedded stars from narrowband nebula image with Spot Healing Brush (I tried StarNet++ in PI but it left many holes in the nebula, so PS was easier with this nebula)
Slight noise reduction in PS for central region of nebula
Layer RGB starfield image on top as a lightness layer (equivalent to a PixelMath “max” instruction in PI). I masked off the regions outside the nebula so that only the RGB starfield would show there.
Save as TIFF and move back into PI

9. Star Reduction
No star reduction necessary. The RGB starfield needed very little stretching, so I left the stars as is.

10. Final
Final Histogram Transformation
ICC Profile Transform to sRGB
Resample to 50% of scale
Save as JPG