Sadr Region

Designation: Sh2-108 – IC 1318
Hemisphere: Northern
Constellation: Cygnus
Distance: 5,000 light years
Object type: Diffuse emission nebula


Sh2-108 is a diffuse emission nebula that seems to surround the bright star Sadr (Gamma Cygni), in the northern constellation Cygnus, and is therefore informally called Sadr Region or Gamma Cygni Nebula.

In reality, Sadr is not embedded in the nebula as the two objects are fairly distant and unrelated. The star, in fact, is around 1,800 light years away whereas the nebula lies a bit farther at approximately 5,000 light years from Earth.

The Sadr Region stretches over 100 light years across, and is mainly composed of hydrogen ionised by a hot blue star hidden behind interstellar dust. This rich complex of glowing dust and nebulosity hosts two more deep sky objects, as shown below.

The young open cluster NGC 6910, discovered by William Herschel in October 1786, contains mostly OB stars as well as some supergiant stars, including the red supergiant RW Cygni. The cluster is believed to be physically related to the Gamma Cygni Nebula.

As a bonus I also captured the Crescent Nebula (NGC 6888), a faint emission nebula that spans about 26 light years across and is located approximately 5,000 light years away from Earth.


Mount: ZWO AM5
Main Telescope: William Optics Redcat 51
Main camera: ZWO ASI294MC-Pro
Main camera filter: Optolong L-Ultimate 3nm
Guidescope: Svbony SV165 30/120
Guide camera: ZWO ASI174MM
Guide camera filter: Astronomik UV/IR cut

Acquisition details

Total integration time: 6 hours
Acquisition: ZWO AsiAir Plus
Processing: PixInsight
Location: Luxembourg

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