The Rosette Nebula (also known as Caldwell 49) is a large spherical ionized atomic hydrogen region (H II region) that is circular in appearance and located near one end of a giant molecular cloud in the Monoceros region of the Milky Way Galaxy. The open cluster NGC 2244 (Caldwell 50) is closely associated with the nebulosity, the stars of the cluster having been formed from the nebula's matter (from Wikipedia).
The nebula is about 5,200 light-years away and spans nearly 65 light-years.
Tech Specs: Sky-Watcher Esprit 120mm ED Triplet APO Refractor, Celestron CGEM-DX mount, Canon 6D stock camera, 27 minutes total integration time at ISO 3200, imaged on February 6, 2018. Location: The Dark Side Observatory in Weatherly, PA.