An hour on the crescent nebula

[R1k]

Crescent “should’ve been named Brain” nebula
1 hour integration

Bortle 6 NW UK

Another image from a night battling the full moon on 21/11/21. I’m surprised at how much detail and faint OIII signal (the blue bubble) has come out in just 1 hour of integration. Really highlights the benefits of shooting with a big and fast (f4) Newtonian with oodles of light gathering capabilities. I’ve gone for a starless image here to show off the structure (and because I haven’t fully optimised the collimation and corrected focuser tilt yet)

 

Equipment:
- Skywatcher EQ6-R pro
- Skywatcher 10 inch f4 Quattro
- Skywatcher Aplanatic coma corrector
- Skywatcher Evoguide 50ED + ZWO ASI 120MM-mini
- ZWO ASI 294MC pro
- Optolong L-eXtreme
- Pegasus Powerbox advance

Acqusition:
- Lights: 12 x 300s at gain 200, offset 30, cooled to -10c
- Darks: 30 from library

Processing:
- APP, Ha and Oiii extract algorithms
- correct vignette and light pollution gradients in APP (no flats)
- on Ha and Oiii images in PS - star removal, topaz denoise, curves, levels, contrast enhancements using high pass filter
- Combine Ha and Oiii images (Ha to red, Oiii to green and blue) denoise and de-texturing of background using layer masks, saturation boost in ACR, further curves adjustments, heavy crop.