Capturing the Cygnus Wall: A Deep Dive into SHO Processing

Recently, I had the incredible opportunity to capture the awe-inspiring Cygnus Wall, a prominent region within the constellation Cygnus. This celestial masterpiece was rendered using the SHO (Sulfur II, Hydrogen-alpha, Oxygen III) narrowband palette, with a touch of RGB stars to bring out the finer details. Join me as I walk through the acquisition and processing steps that brought this image to life.

Acquisition Details

All data was acquired from my backyard, blessed with a Bortle 5 sky, utilizing NINA for control and PHD2 for guiding. The imaging session spanned several hours to gather the necessary narrowband and RGB data.

• Acquisition Date: July 5, 2025
• Location: Backyard (Bortle 5)
• Software: NINA, PHD2

Narrowband Data:

• SII: 16 x 300" (1h 20m)
• Ha: 18 x 300" (1h 30m)
• OIII: 17 x 300" (1h 25m)

RGB Data:

• R, G, B: 16 x 30" (8m each)

Camera Settings:

• Gain: 200
• Offset: 55
• Temperature: -5°C

Calibration Frames:

• Darks: 50
• Flats: 30
• Dark Flats: 30

Equipment

My setup for this capture included:

• Telescope: GSO RC6
• Camera: ZWO ASI2600MM Pro
• Filters: Antlia V-Series LRGB and SHO 3nm Narrowband Filters, 2" Mounted
• Filter Wheel: ZWO Filter Wheel
• Focuser: ZWO EAF
• Mount: iOptron GEM 28
• Off-Axis Guider: ZWO OAG-L with ASI174MM Mini

Processing Workflow

The processing journey involved several key steps using DeepSkyStacker (DSS) and Adobe Photoshop:

1. Stacking: All acquired sub-frames were meticulously stacked in DeepSkyStacker.
2. Initial Stretch: A first stretch was performed in Photoshop to reveal the initial structures of the nebula.
3. Star Removal: StarXTerminator was employed to create a starless version of the image, allowing for more focused adjustments on the nebular details.
4. Nebula Enhancement: A second stretch was applied to the starless image to further enhance target details.
5. Color and Contrast: Curves adjustments were used to fine-tune contrast, followed by saturation and color adjustments to bring out the vibrant hues of the SHO data.
6. Noise Reduction: NoiseXTerminator was used to clean up any remaining noise.
7. Sharpening: The Smart Sharpen filter was applied to bring out finer details.
8. Star Integration: Finally, the original RGB stars were reintegrated into the image using a screen layer, adding a crucial element of realism and sparkle.

This process allowed me to reveal the intricate structures and beautiful colors of the Cygnus Wall, a testament to the power of narrowband imaging and careful post-processing.

I hope you enjoyed this look into the capture and processing of the Cygnus Wall! For more of my astrophotography work, feel free to check out my Instagram: