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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.
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GB-F400.jpg)