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The Hole in the Trees Skybox | all galleries >> Deep Sky >> Planetary Nebulae > NGC 2022
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NGC 2022

PK 196-10.1 in Orion

Bicolor Ha/OIII image, using OIII as luminance and Ha/OIII for color in the nebula core, colorized OIII for the halo, and RGB for stars.



Exposure: Total exposure time about 32 hours, 29 x 20mins Ha, 34 x 20 mins OIII, 15 x 2 mins each channel for RGB. All bin 1x1. Captured over many nights from October 2017 to January 2018.
Light pollution: Bortle 8 (white zone, NELM about 4.5)
Image scale at capture: 0.6 arcsecs/pixel = f/5.7
Scale of presentation: 0.6 arcsecs/pixel (full 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 5nm Ha/SII, 3nm OIII, Type IIe LRGB
Rotator: Optec Pyxis 2", connected via Andy Galasso's 0.4 driver (Optec Pyxis Rotator AG)
Focuser: Rigel Systems GCUSB_nStep with driver version 6.0.7
OAG: Orion Thin OAG
Guide cam: Lodestar (first generation). 4 second exposures
Automation SW: Sequence Generator Pro 3.0.0.4 beta
Guide SW: PHD2.6.3, connected to guide cam via native SXV driver
ASCOM: ASCOM 6.3.0.2831
Platesolving: PlateSolve 2, with 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 1.85

1. Calibration
BatchPreProcessing with flats, darks and bias, using Cosmetic Correction with master dark

2. Stack and Mure Denoise
Blink to preview and reject a few frames
Subframe Selector to confirm selections and weight by FWHM and SNR
Image Integration
Mure Denoise

3. Luminance Linear Processing
Dynamic Crop
Dynamic Background Extraction
Deconvolution with Dynamic PSF

4. Luminance Stretching
Histo Transformation
Curves Transformation
Noise Reduction with TGV Denoise and Multiscale Median (following
David Aultís Astro Imaging Channel tutorial).
Local Histogram Equalization to enhance contrast inside nebula
(Halo and core processed separately)

5. RGB Linear Processing
LRGB Combination to merge RGB channels
Dynamic Crop (using the same icon as with luminance)
Dynamic Background Extraction
Photometric Color Calibration

6. RGB Stretching
Histogram and Curves Transformations

7. Color
Merged narrowband channels in PixelMath: mapped Ha to R, OIII to green and blue
Halo is OIII only, colorized to teal blue with PixelMath
LRGB Combination: used OIII as luminance on core, boosted saturation

8. Combine
In Photoshop, used Minimum Filter to erode overexposed core out of halo image
With PixelMath, used max function to blend core, halo and RGB star field images

9. Final
In Photoshop, clean up blue comatic halos on color layer with Radial Blur and save as TIFF



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