This is a hybrid image, perhaps the Contest Gods will still allow it. The red is all-Pentax, all the time, photographed through a telescope. This is part of the North American and Pelican nebulae; I enhanced the Pentax image by shooting another with the same optics on an ASI 183MM-Pro monochrome astro camera through a 7-nm hydrogen-alpha filter, registering that with the DSLR one, and setting the blend mode to "Luminosity" in Photoshop. The astro camera greatly enhances the fine detail, while the DSLR provides the color and the basis of the image. What you're looking at is primarily hydrogen gas, excited by starlight impinging on it and re-emitting at its characteristic 656-nm wavelength, hence the red color. Full technical details, as well as this image's location in the sky, can be easily found at
astrobin.
Similar Threads 
