Sh2 140 - The Bright Rim

Sh2-140 or the Bright Rim is an emission and reflection nebula in the constellation Cepheus. The bright open star cluster Pismis-Moreno 1 features multiple young and hot stars that emit intense UV-radiation to ionize the surrounding medium. This manifests in a dark red Hydrogen-alpha emitting emission nebula called Sh2-140 or LBN 505. It also impacts a dense and cold dark nebula cloud creating a bright rim of reflected light from the cluster producing a slightly gray and orange hue.

The image also features numerous bright blue star which are members of the Cepheus OB association, a compared to star clusters more widespread population of young luminous O and B class stars which form in filaments rather than concentrated clusters. One of them includes a thin blue reflection nebula LBN 500. In the bottom right corner of the image are parts of the outer region of Sh2-145, another emission nebula in the vicinity of Sh2-140 which is rarely captured on its own.

Photographed from Trevinca, Spain under Bortle 2 conditions.