Cosmic Bubble Ablaze

This bicolour image of the Bubble Nebula (NGC 7635), an emission nebula in the constellation of Cassiopeia, was shot with a telescope from the suburbs of Toronto using narrowband filters to capture the glowing hydrogen (orange) and oxygen (blue) emission. The oxygen emission was boosted to generate the cool blue central region of the image and provide a sense of the bubble floating in 3D within an inferno of glowing hydrogen.

This image was an Editor's Choice selection by Sky and Telescope in September 2021.