RCOS 16" RC @ f/8.4
SBIG STL 11k
Astrodon Series I LRGB

    plus 6 nm Ha


(HaL)(HaR)GB:

Ha = 30 min x 7, 1x1
L =
  15 min x 30, 1x1
R =
 15 min x 11, 2x2
G =
 15 min x 11, 2x2
B =
 15 min x 11, 2x2

Image data acquired
remotely at New Mexico
Skies.

Processed with CCDsoft,
Registar, Sigma
Combine,
CCDsharp,
Neat Image, and Adobe
PS.
M101, aka NGC 5457,
aka the Pinwheel Galaxy,
is located about 27
million lightyears away in
the constellation Ursa
Major. It spans about
170,000 lightyears in
diameter, corresponding
to an angular size of 22
arcminutes. It is a large
and asymmetrical spiral
galaxy. Note the reddish
HII regions in the spiral
arms, representing areas
where hydrogen is slowly
compressed over millions
of years to form new stars.
M101 -- Click on image to enlarge
   Mouseover image to see 1st
     attempt from 4 years ago