Butterfly Nebula: The most prominent constellation in the northern summer sky is Cygnus, the Swan, also called sometimes the Northern Cross. The central star of the cross is Sadr, which you see at the lower edge of the image. Around this star there is a faint, not very prominent nebulosity. The brightest parts of the nebula are called Butterfly Nebula, displayed in the center. Young hot stars have created the nebula by its very intense radiation.
On the right hand side of the image you find the Open Cluster NGC 6910.