The Witch Head Nebula, IC 2118
   Click on image to enlarge
4" Takahashi FSQ @ f/5
SBIG STL 11K
Astrodon Series I Filters

3 panel mosaic, with about
15 hours total imaging time
-- most of the data was
accumulated with 20
minute integrations, except
for the area around Rigel,
which was layered with 1
minute exposures to better
deal with the extreme
brightness

Processing was with
CCDsoft, Registar, Neat
Image, and Adobe P
S
The Witch Head Nebula
(in Eridanus) is a large
region of nebulosity that
shines by the reflection
of light coming from the
massive star, Rigel (in
Orion.) Dust particles  
reflect blue wavelengths
more efficiently than red
or green; hence, the
predominance of blue in
the nebula. The same
process in our sky
causes it to appear blue
(most of the time.)