Emission and Reflection Nebulosity in Orion

Uploaded 2/25/06

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This unique object in the constellation of Orion lies on the southwest edge of the Lambda Orionis hydrogen bubble. Although it is extremely faint, it displays a stunning combination of red hydrogen gas and blue dust, with a golden brown hue to the lower left which is dust that is obscuring the interstellar backdrop.

The central star is GSC700:1015 and is a 5.8 magnitude B1 star, with a blue color index of -.128. The nebulosity is illuminated by this hot star out to a distance determined by the reach of the intensity of the ionizing radiation. Then, you see the blue nebulosity alone. When the illumination is again too dim to show the blues, you then see the yellow browns illuminated by local starlight. Plenty of physics going on here.

Composition on this one was tough! I knew the outline of the nebula was not centered on the bright star, but the blue part on the left had a vague boundary.

Processing: 80 minutes of Halpha data was combined and processed separately. Each color frame was a full size unbinned set of exposures, which when combined produced the primary image of the object. When I was satisfied that the RGB image was as good as it could be, I then extracted the red channel, combined it with the Ha data with a mix of 80/20% then combined that image with the R channel again with Lighten in PS to bring back all of the stars to full brightness. Thus when combined with the B and G channels, the stars are perfect G2V balanced, and we retain all of the blue and golden yellow nebulosity that was present in the original RGB image.

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: Ha^RGB = 60:20:20:20 RGB Combine Ratio: 1: 1.05: 1.11 Filters: AstroDon RGB Tricolor Location: Payson, Arizona Elevation: 5150 ft. Sky: Seeing FWHM = 6 arcsec (Maxim DL - 10min subframe), Transparency 9/10 Outside Temperature: 35 F CCD Temperature: -30 C Processing Tools: Maxim DL, Gralaks Sigma, Photoshop, PixInsight, Starazona Debloomer. HOME GALAXIES EMISSION NEBS REFLECTION NEBS COMETS GLOBULARS OPEN CLUST PLANETARIES LINKS


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