[2] It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (HD 192163) colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 250,000[3] to 400,000[citation needed] years ago.

The inward moving shock wave heats the stellar wind to X-ray-emitting temperatures.

The Crescent Nebula is a rather small object located about 2 degrees Southwest of Sadr.

While considered bright by astronomical imaging standards, visually it is relatively faint.

Under favorable circumstances a telescope as small as 8 cm (with filter) can see its nebulosity.