The Medusa Nebula is a planetary nebula 1500 light years away in Gemini. It is small and dim for my small scope; 10 arc min in apparent size and 16th magnitude. This is a Ha, Oiii narrow band image with a one shot color camera. The Ha is naturally red and the Oiii is blue-green. The narrow band filter lets me capture this under the Austin light dome, from my Bortle scale 7 driveway.
The Hubble palate orders narrow band filters red to blue regardless of their natural color an can be expanded to include more than three filter colors. The 3 color Hubble palate is SHO (red Sulphur, green Hydrogen, and blue Oxygen) and is commonly used enough that many people think of those colors as natural. A OSC camera registers Oiii in both the blue and green channel. I've balanced the two band, HOO (red Hydrogen alpha, green and red Oxygen III) palate here, for a more natural look than the Hubble palate.
William Optics RedCat 250/51 mm telescope, Optolong L-eNhance filter, ZWO ASI-533 MC camera cooled to -10C. 24 180" exposures for 72 minutes of total integration. Processed in PixInsight, noise reduction in Topaz DeNoise, and final crop and exposure in PhotoShop.
Content created: 2021-04-08
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