The Cone Nebula forms part of the nebulosity surrounding the Christmas Tree Cluster. The nebulosity in this region is part of the Gamma Cygni Nebula. As the plerion ages, the nebulosity of the supernova remnant dissipates and disappears. Initially a small, faint nebulosity, subsequent observations showed that something remarkable had happened to it. An 'n' is appended if the cluster lies within nebulosity. However, the bright nebulosity that surrounds this star makes the observation uncertain. The brightest nebulosity, later listed as NGC 1977, was discovered by William Herschel in 1786. The whole area of nebulosity is often referred to as NGC 6820. It is not yet clear if the surrounding nebulosity is associated with the star itself. Early attempts at classification were confused by the interpretation of surrounding nebulosity as companion stars. Observations in 1944 and 1945 showed a somewhat elongated nebulosity around wide and long. The Alnitak system is bathed in the nebulosity of IC 434. In addition, studies of outlying nebulosity suggest at least one earlier eruption around AD 1250. Only a trace of reflection nebulosity remains. Meissa is surrounded by a ring of nebulosity about 12 degrees across.