This is the Rosette Nebula in HAlpha narrowband.
The Rosette Nebula is a large spherical Hydrogen Alpha region located in the constellation Monoceros.
The cluster and nebula lie at a distance of some 5,000 light-years from Earth and is roughly 130 light years in diameter.
The open cluster NGC 2244 is closely associated with the nebulosity being the stars of the cluster which have been formed from the nebula's matter.
The complex has the following NGC designations:
NGC 2237 – Part of the nebulous region (Also used to denote whole nebula)
NGC 2238, NGC 2239 & NGC 2246 – Part of the nebulous region
NGC 2244 – The open cluster within the nebula
This images total exposure time was 2 hours and 30 minutes, consisting of 15 x 600 second 7nm narrowband H-Alpha subs.
Taken through a 80mm Refractor @ f6.25, on a hypertuned CGEM mount with QHY268M camera.