Description:
Sh2-284 is a large H II emission nebula in Monoceros, about 15,000 light-years away, powered by the young star cluster Dolidze 25. Intense ultraviolet radiation from these massive stars ionizes the surrounding gas, producing strong H-alpha emission (red color at 656.3 nanometers) alongside regions rich in doubly ionized oxygen (O III) (blue color at 500.7 nanometers).
The O III highlights hotter, more energetic zones—often tracing shock fronts and cavity edges—while dark dust lanes and pillars cut through the glowing gas. Together, these features reveal an active star-forming region shaped by stellar radiation and winds, and make Sh2-284 a striking target for narrowband astrophotography.