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Scope: C8 at f/3.3, Location: Dos Picos Park, Ramona, CA 25 August 2006, Camera: Artemis285
Exposure: 8 x 240 sec H-Alpha (1x1), 8 x 120 sec IR/UV Block Filter (1x1), 8 x 90 sec RGB Exposures (2x2).
Processing: Images were captured with Artemis Capture (as FITs). Aligned/stacked in Registax 3 and saved as FITS. Luminance, H-Alpha, IR/UV Block, and Color channels were scaled and color balanced in Astroart. Channels were co-registered in Astroart. Central Gradient removal was done in Astroart. Curves and Levels applied in Photoshop to optimize object features. Luminance construction consisted of the H-Alpha exposure mixed with the IR/UV Block exposure. Final LRGB combine was done in Photoshop using Luminance Layering (or LLRGB) - G2V calibration factors and Atmospheric Extinction factors were applied. Selective sharpening was applied to nebula features in Photoshop with a layer mask. . Final Image size is approximately 1390x1043.
All exposures in this image were guided; North is up in this image. M17 is sometimes known as the Swan Nebula, sometimes as the Omega Nebula, and sometimes as the Horseshoe Nebula. This region is a star forming region with your stars exciting surrounding Hydrogen to light emission. Lighter central bar is believed to emit reflected light from the brighter stars as well. Distance estimates vary but the approximate distance from Earth is about 5,000 light years. This image replaces and earlier image that can be seen in the Archives here . The Horizontal FOV is 46'.
Image center is located approximately - Equatorial 2000: RA: 18h 20m 35s Dec: -16°10'49"