The Gamma Cygni Nebula, also known as the Sadr Region or IC 1318, is a diffuse emission nebula that can be seen around Sadr (Gamma Cygni), the star at the center of the Northern Cross, which marks the heart of Cygnus. (Star is near the top of image)  Despite the name, the star and the nebula are unrelated. Even though it looks embedded in the nebulosity, Sadr is approximately 1,800 light years distant, while the nebula is much further away, at 4,900 light years.

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The Gamma Cygni Nebula is considered an emission nebula because it is ionized by the radiation of the nearby stars and it emits visible light as a result. The visible portion of the H II region stretches over an area more than 100 light years across. The nebula is illuminated by an O9-class star which is visually obscured by interstellar material.

The Sadr Region is very easy to find in the sky. Sadr is one of the bright stars of the Northern Cross and it marks the heart of the celestial Swan. It is a white supergiant star with an apparent magnitude of 2.23. With 12 solar masses and 150 times the Sun’s radius, the star is about 33,000 times more luminous than the Sun.

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Objects in this image: Gamma Cygni Nebula, Crescent Nebula, Sh2-108, LBN 234

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Lens: Canon 100mm USM L Macro Lens

Camera: QHY 163M

Mount: iOptron CEM40

Total exposure timing: 3 hours 

Antlia 3.5nm Ha, Sii, Oiii (1 hour each)

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