The Butterfly and Crescent Nebulas – Elemental Colors

About This Photograph

In the heart of the constellation of Cygnus lies a vast complex of colorful and chaotic clouds of gas and dust made visible by the bright stars nearby. In the upper left is the Butterfly Nebula, bisected by a dark lane of dense dust and gas seen in silhouette. The bright star to the lower right of this is Gamma Cygni, also known as Sadr, the central star in the Northern Cross.

Following the clouds and tendrils of glowing gas toward the bottom of the photograph leads to the enigmatic Crescent Nebula, the expanding outer layers of a rare Wolf-Rayet star near the end of its life. Long ago, as a red giant, it shed its outer layers into the surrounding space. Now completely depleted of hydrogen fuel, the star fuses helium in its core and expels an energetic stellar wind that collides with the earlier material, shocking it into luminescence.

This photograph was taken using special filters to isolate light emitted by sulfur (red), hydrogen (green), and oxygen (blue).

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