Rosette Nebula in HOO

The Rosette Nebula is a large, circular emission nebula located in the constellation Monoceros, the Unicorn. In the Milky Way, about 5,000 light-years from Earth. The Rosette Nebula is composed of hydrogen gas, dust, and plasma, which give it its red colour (due to ionized hydrogen emitting H-alpha light). At its heart is the open star cluster NGC 2244, composed of young, massive stars. These stars formed from the nebula's material and their stellar winds and radiation have created a cavity in the nebula.