Rosette Nebula

This 51-minute stack gradually revealed the Rosette as more than a red cloud. The dark center and bright knot of stars make the whole nebula look almost hollow, with its glowing gas spreading outward like petals.

The stars in the center belong to the young cluster NGC 2244. Their radiation makes the surrounding hydrogen glow, while their stellar winds push gas away and carve out the cavity in the middle of the Rosette.

The scale is hard to hold in your head: the nebula is about 100 light-years across and roughly 5,000 light-years away. The tiny-looking cluster in the photograph is actively reshaping that enormous cloud.