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A clam in Cygnus

Ryan Génier from Kitchener, Ontario, Canada

Emission nebula Sharpless 2–119 in Cygnus is also known as the Clamshell Nebula. Its ring-like appearance is thanks to the shell of ionized gas — called a Strömgren sphere — surrounding an association of hot, massive stars. (The Rosette Nebula consists of a similar set of features.) This imager took 49 hours of SHO exposure with an 8-inch RASA.