This image was obtained with the wide-field view of the Mosaic camera on the KPNO 0.9m-meter telescope at Kitt Peak National Observatory. NGC 6820 is a diffuse emission nebula that surrounds the open cluster of stars NGC 6823 (at the center of the image). The intense light from the hot, massive stars in the cluster is blowing away the gas in the nebula, causing the distinctive “pillar” shapes on the left side of the image. The image was generated with observations in Hydrogen alpha (red), Oxygen [OIII] (green) and Sulfur [SII] (blue) filters. In this image, North is up, East is to the left.
NGC 6820 is a small reflection nebula near the open cluster NGC 6823 in Vulpecula. The reflection nebula and cluster are embedded in a large faint emission nebula called Sh 2-86. The whole area of nebulosity is often referred to as NGC 6820.
Open star cluster NGC 6823 is about 50 light years across and lies about 6000 light years away. The center of the cluster formed about two million years ago and is dominated in brightness by a host of bright young blue stars. Outer parts of the cluster contain even younger stars. It forms the core of the Vulpecula OB1 stellar association