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Soul Nebula

Westerhout 5 - back to list

Soul Nebula

click image to see full size (3008x3008px)

The Soul Nebula, also known as Westerhout 5, is an emission nebula located in Cassiopeia, 7500 light years away from us. Wikipedia

Acquisition Details

Dates October 25th, 2022 (New Moon)
Frames 50x300” (5mins), 4 hours and 10 minutes of total integration time
Focal Length 287mm (f/4.7)
Camera ZWO ASI533MC-Pro (gain 100, cooled at -10°C)
Telescope TS-Optics Photoline 60mm Doublet Apochromatic Refractor
Accessories 0.8x Flattener/Reducer
Filters Optolong L-Extreme 2” Narrowband Filter
Mount Sky-Watcher EQ6R-Pro
Guide Scope Angeleyes Mini Guidescope 30mm f/4
Guide Camera ZWO ASI 120MM mini
Computer ZWO ASIAIR Pro

Processing Details

I stacked the lights frames in Siril using the OSC Preprocessing Without DBF (Darks, Biases, Flats) script. I decided not to use any Dark, Bias or Flat frames. I might try to create a dark frame library later, but the ASI533MC-Pro is considered a camera that can do without darks given the absence of amp glow.

I tried to process the image to replicate the so called “Hubble Palette” where Hydrogen gas usually has a orange hue and Oxygen gas is blue. At the bottom of the page there is an example of the same image but processed in a more “natural” way, where the nebula is appearing only red.

I then used the following tools:

  • Photometric Color Calibration
  • Remove Green Noise
  • Generalized Hyperbolic Stretch (GHS) Transformations
  • StarNet Star removal
  • Split Channels
  • RGB Compositing (Luminance->Red, Red->Red, Green->Red, Blue->Green)
  • Color Saturation
  • Star Recomposition with some stretching and reduction of the starmask

Additional Images