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Oxygen swells in Cygnus

Team FACT: Louis Leroux-Géré/Cédric de Decker/Vincent Martin/Thibault Rouillée, taken from Starfront Observatories

The Milky Way constellation of Cygnus is filled with seas of hydrogen gas, but 20 hours of exposure with an OIII filter uncovered rarely seen filaments of oxygen, glowing blue in this image. This vista spans more than 6°, encompassing emission nebulae Sharpless 2–115 at left and LBN 331 on the right. The final image comprises 66⅔ hours of Hα/OIII/RGB data taken with a 2.8-inch f/5.6 astrograph.