The Crescent Nebula is an emission nebula in the constellation Cygnus, about 5000 light-years away from Earth. It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (HD 192163) colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 250,000 to 400,000 years ago. The result of the collision is a shell and two shock waves, one moving outward and one moving inward. The inward moving shock wave heats the stellar wind to X-ray-emitting temperatures.
Data captured over 5 nights between 21st & 28th September, 2018.
39x 10 minute exposures with Ha filter.
63x 10 minute exposures with Oiii filter.
Total Exposure 17 hours.
Skywatcher Quattro 200 CF
Atik 428EX Mono
This image was processed in Pixinsight & Lightroom.
Calibration and Registration using Batch PreProcessing script.
Dynamic Crop - Cropped to remove any black edges.
Dynamic Background Extraction - Applied to remove background gradients.
Multiscale Linear Transform - Noise reduction.
Histrogram Transformation - To stretch the image and bring out the data.
Curves Transformation - To increase contrast.
UnsharpMask - To sharpen detail in core, with sharpening mask in place to target nebula.
Curves Transformation - To boost saturation.
Export as JPEG and import into Lightroom.
Increase contrast (+25)
Reduce Highlights (-10)
Export final JPEG for upload.