NGC206 Region in M31

Enhanced Hydrogen Comparison

Star Clouds and Emission Nebula in Andromeda

Uploaded 12/12/06

This 4 hour image is a deep LRGB that is G2V calibrated 

Select an image size for a larger view: 1024 x 768 1600 x 1200

 Same image with an additional 3 hours of hydrogen data added (7 hours)

Select an image size for a larger view: 1024 x 768 1600 x 1200

This pair of images should once again satisfy both imaging camps, the purists will prefer the left shot, a well exposed standard LRGB image with G2V calibrated colors. The right image will satiate those with a sound curiosity as to the dynamic relationships between hot O/B associations and their surrounding hydrogen. I have previously posted a description of the left image here.

Comparing the two images.

Most evident from the larger versions of the right image is the direct relationship between hot blue stellar associations and red nebulosity. In many cases, the nebulosity forms partial or complete shells of material around the stars, such as the stunning round bubble at the very bottom of the image. Surprisingly, NGC206 which is the very bright stellar grouping in the center of the image - a mere spur in the blue arms of the galaxy, is permeated with large amounts of hydrogen gas. Near the top of the image, another very large hydrogen region appears associated with the blue arm stars above it. And the tattered remains of many other small patches of gas are very apparent, making it a wonderland for nebulous exploration!

Processing notes:

Combining deep hydrogen exposures with a normal image is not a simple straightforward task. The primary difficulty is to remove the red continuum from the Ha data and all of the stars, so it can be combined by "Screen" in Photoshop and retain the most faint tendrils of nebulosity as possible. First, stars were removed by subtracting the blue data, and a synthetic flat field was created from this image. This flatfield with no stars was combined with "Screen" with both the red channel at 100%, and blue channel at 15% for the final RGB set.

Instrument: 12.5" f/5 Home made Newtonian Platform: Astrophysics 1200 QMD CCD Camera: SBIG 10XME NABG with Enhanced Water Cooling Guider: SBIG ST4 Exposure: LRGB = 120:40:40:40 (RGB NOT Binned) For Enhanced image add 3 hours of Ha Data RGB Combine Ratio: 1: 1.05: 1.11 = G2V Filters: AstroDon RGB Tricolor Location: Payson, Arizona Elevation: 5150 ft. Sky: Seeing FWHM = 5 arcsec (Maxim DL - 10min subframe), Transparency 9/10 Outside Temperature: 35 F CCD Temperature: -30 C Processing Tools: Maxim DL, Gralaks Sigma, Photoshop, PixInsight, Starizona Debloomer. HOME GALAXIES EMISSION NEBS REFLECTION NEBS COMETS GLOBULARS OPEN CLUST PLANETARIES LINKS


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