Hemisphere:  Northern  ·  Contains:  Bubble nebula  ·  NGC 7635
Getting plate-solving status, please wait...
The Bubble Nebula in SHO Hubble Palette, 


            Josh Woodward
The Bubble Nebula in SHO Hubble Palette
Powered byPixInsight

The Bubble Nebula in SHO Hubble Palette

Technical card

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, 2019Aug. 23, 2019

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

Basic astrometry details

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.



Josh Woodward
License: None (All rights reserved)

Sky plot

Sky plot


The Bubble Nebula in SHO Hubble Palette, 


            Josh Woodward