Veil Nebula

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Image data by Mike Cook.
Six frames from his SBIG ST-10 CCD camera using red, green, blue, H-alpha, O-III, and H-beta filters on an Astrophysics 130mm f/6 refractor. Colorimetric and spatial processing was used to combine the frames into this final image. The hues and relative intensities are correct (to within the calibration accuracy of Mike's filters and sensor, and the limits of the display)

Colorimetrically Rendered Veil Nebulae

The Veil Nebula is a supernova remnant- a star exploded, casting off a shell of gas that expands outward. The gas is hot and ionized and emits light at characteristic wavelengths. Hydrogen glows red at a characteristic 656nm, and also a blue-green at 486nm. Ionized oxygen emits gree-blue light at 501nm. Most pictures of the Veil show a bright red cloud because the red H-alpha light is easy to record on film and CCD sensors. It is a challenge to display the blue-green colors because it falls in the gap between the blue and green-sensitive layers of film, and other imaging systems.

This picture was created by combining six frames carefully obtained by Mike Cook into an RGB color space suitable for display. It reveals a dominant blue-green color instead of the customary red. The details of the color processing are described on my pages about line-spectra colorimetry.