The Cocoon Nebula
- Date Posted: July 20, 2006
- Resolutions: 2184x1472 , 2184x1472 , 2184x1472
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This LRGB image of the Cocoon Nebula was taken over two nights spanning July 20 to 22. It is my third target with CCDAutopilot 3. Of course it was taken with The BRC-250, ST-10XME, CFW-10 filter wheel with Astrodon E-series filters, Finger Lakes Instruments DF2 focuser, and Optec Pyxis rotator on the MI-250 mount and Pier-Tech 3 pier from the Dark Horse Observatory in Kimberton, PA. The seeing varied from a FWHM of 3.0 to 4.95, briefly, with a mean FWHM of around 3.5 for most of the time. The weather conditions were suboptimal with intermittent thin clouds drifting by despite predictions for a clear night. This produced patchy background areas of noise in the stacked images. Total exposure was L = 150 minutes, RGB = 60 minutes each. All images were taken as 10 minute subexposures, all unbinned. Processing was a challenge due to background noise. In fact I have reprocessed this four times. Had the weather and time permitted I am certain that more exposures would have been helpful. CCDStack processing to flatten the background was used. MiraPro Professional was used to align LRGB frames in common. Then the luminance and RGB images were calibrated, debloomed, airplane trails removed, normalized, and sigma-reject sum combined in CCDStack. The RGB color was also combined in CCDStack using a combine ration of Red = 0.9, Green – 1.1, and Blue = 1.3. The luminance and RGB combine were then adjusted with levels and curves in Photoshop CS2. Russel Croman’s gradient exterminator was applied. A luminance-combine was done in PhotoShop CS2 with fine adjustments of levels and curves, saturation and contrast. Then Noel Carboni’s Astronomy Tool for reducing star size was applied, followed by a light unsharp mask filter - faded 50%. I hope that you enjoy it. Suggestions for improvement are always appreciated.
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- Christopher Abissi
- January 19, 2022
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