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This is the constellation, Cygnus, the Swan. Cygnus is a summer and
fall constellation lying astride the Milky Way Galaxy as can be obviously
seen in this image. The background star clouds are our view of the outer
regions of the Milky Way's disc. North of this point (upper right corner
in this image) the Milky Way thins out substantially as we are looking out
and away from the center of the galaxy.
The stars making up the endpoints of the traditional stick figure of the
constellation have been slightly blurred to make them more visible in this
image. The five central stars make up the asterism, the Northern
Cross. The brightest star in the upper right quadrant is Deneb.
At magnitude 1.25, Deneb is one of the signpost stars we use to identify the
constellation and marks one corner of the asterism, the Summer Triangle
along with Vega in Lyra and Altair in Aquila. The center star is Sadr
at magnitude 2.23. On the south end of the constellation (lower left)
is the famous and beautiful double star Alberio. Visually, this pair
of stars presents a striking contrast of both color and brightness with one
star being a bright blue star and the other being a dimmer orange-gold
color.
Cygnus contains many famous nebulae as well including the
North American and Pelican nebulae
just northeast (up) from Deneb. Just south of Cygnus' east wing lies
the Veil Nebula Complex just visible in
this image. The Crescent Nebula lies just south of Sadr as does the
open cluster M29. Also around Sadr, primarily to the northeast is the
Gamma Cygnus Nebula. Gamma Cygnus is the Bayer designation for Sadr
which is the source of radiation for this emission nebula. The reddish
color of these light years large clouds of gas is a result of hydrogen alpha
light being emitted from this gas which is primarily hydrogen.
Date: 10/21/2006
Location:
Cheddar Ranch Observatory
Telescope: Canon 28-135 telephoto @ f/3.5
Mount: LXD55
Camera: Canon 350D,
Type 1 filter, ISO 400
Exposure Count: 41 x 3 minute, 123 minute total
exposure
Guiding: None
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Post Processing: |
ImagesPlus: Dark and flat calibration, align and
combine, digital development, pixel math, star/halo size reduction
Photoshop CS2: Unsharp mask, levels, layer mask
blur for stick figure stars
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