Sunday, July 22, 2007

Dumbell Close up

Here is a close up image of Messier 27, the Dumbell Nebula, as seen in an earlier post. This image was taken with a monochrome CCD camera using a special color filters to give color to the black and white image. The object is shown here in the combined light from Oxygen III, and Red. Oxygen III, or OIII is the wavelength of light given off by interstellar ionized Oxygen. A special filter was used to separate it out from the normal visible light spectrum. The light normally given off by M27 lies in the red and OIII regions.

*Warning - Technical stuff*
Light from interstellar objects comes in three flavors. It is Red from Hydrogen Alpha (HA) gas, Blue from cooler Hydrogen Beta (HB) gas, and Teal/Green from ionized Oxygen (OIII). These three color sources make up the Red/Green/Blue light our eye registers when looking at these types of objects.
Normally the cooler Hydrogen Beta is found in mostly the same places you will find Oxygen (OIII), so you can use the data from OIII and double it to serve as green and blue for the color separation process, and get a result close to the original. This is the basis of the Two Filter - Three Color process in use in this image. The Green and Blue channels are composed of OIII light, and the Red channel is from Red light. I did it this way because I was not satisfied with my Green and Blue filters and did not yet own a Hydrogen Alpha filter.
It seemed to work out OK. Sometimes Rocket Science really isn't Rocket Science.

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