Imaging telescopes or lenses: Celestron C8 Starbright
Imaging cameras: ZWO ASI 1600MM Cooled Pro
Mounts: Orion (Synta) Atlas EQ-G
Guiding telescopes or lenses: Celestron C8 Starbright
Guiding cameras: ZWO ASI 290MM mini
Focal reducers: Celestron Focal Reducer/Flattener x0.63
Software: PHD2 Guiding · Stellarium · EQMOD · DeekSkyStacker (DSS) · SharpCap · PixInsight 1.8 · StellariumScope · Seqence Generator Pro
Filters: ZWO L 1.25" · ZWO Blue 1.25" · ZWO Green 1.25" · ZWO Red 1.25"
Accessory: OAG · ZWO EFW 8x 1.25" · QHYCCD QHY PoleMaster · Rigel Systems nStep
Dates:Aug. 22, 2019 , Aug. 23, 2019
Frames:
ZWO Ha 1.25": 183x180" (gain: 300.00) -15C bin 1x1
ZWO OIII 1.25": 174x180" (gain: 300.00) -15C bin 1x1
ZWO SII 1.25": 164x180" (gain: 300.00) -15C bin 1x1
Integration: 26.0 hours
Darks: ~25
Flats: ~20
Flat darks: ~20
Avg. Moon age: 21.55 days
Avg. Moon phase: 56.31%
Bortle Dark-Sky Scale: 5.00
Temperature: 25.00
Astrometry.net job: 2885559
RA center: 23h 20' 37"
DEC center: +61° 10' 30"
Pixel scale: 0.617 arcsec/pixel
Orientation: 269.872 degrees
Field radius: 0.350 degrees
Resolution: 3312x2396
Locations: backyard, Chico, CA, United States
Data source: Backyard
This is my fifth iteration of trying to create a satisfying Hubble Palette image of the Bubble Nebula.
I first registered the the images to Ha using Star Alignment. I then used Dynamic Crop to clip off stacking artifacts and coma in the corners. Next, I used Linear Fit to with Ha as the reference to calibrate SII and OIII. I then used ABE separately on OIII, Ha, and SII. I then combined the images using PixelMath.
With this version I went with a PixelMath combination of:
Red - SII * 0.8 + Ha*0.2
Green - Ha*0.85 + OIII*0.15
Blue - OIII*0.9 + Ha*0.1
I then did a 90% SCNR to remove the remaining green cast
I was having problems with a purplish background until I used Background Neutralization..
SHO images tend to err towards green because Ha overwhelms OIII and SII. To combat this, I adjusted the green hue towards orange/yellow using Curves hue adjustment. I then used Jon Rista’s NR techniques with TGV Denoise and MMT.
I stretched the image using Histogram. I used ACDNR to with a strong mask to remove the “black tail”. I used a mild Color Saturation to boost the color paying special attention to the light blue of the “Bubble”. I used HDRMT to draw out hidden details. Then Morphological Transformation to reduce star size. Lastly, I used Curves for sight contrast and saturation enhancements.
| Cloudy Nights |
| Schmidt-Cassegrain Telescope (SCT) Imagers |
| ZWO ASI1600MM/QHY163M |
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