Seen as a seagull and a duck,
these nebulae are not the only
cosmic clouds to
evoke images of flight.
But both are winging their way across this broad
celestial landscape, spanning almost 7 degrees across
planet Earth's
night sky toward the constellation of the Big Dog
(
Canis Major).
The
expansive Seagull
(top center)
is itself composed of two major cataloged
emission nebulas.
Brighter NGC 2327 forms the head with the more diffuse
IC 2177 as the wings and body.
Impressively, the Seagull's
wingspan would correspond to about 250
light-years at
the nebula's estimated distance of 3,800 light-years.
At the lower right, the Duck appears much more compact and
would span only about 50 light-years given its
15,000 light-year distance estimate.
Blown by
energetic winds from an extremely massive,
hot star near its center, the Duck nebula is cataloged
as NGC 2359.
Of course, the Duck's thick body and winged appendages
also lend it the slightly more
dramatic popular moniker,
Thor's Helmet.