Sh2-274, as listed in the Sharpless catalog, is commonly known as the Medusa Nebula. It is located in the constellation Gemini approximately 1,500 light-years distant. Most of the celestial objects imaged by amateurs have been known dating back to the eighteenth century. The Medusa Nebula is an exception. It was first discovered by George O. Abell in 1955. The filaments of glowing gas winding through the nebula suggested the "serpent hair" of Medusa in ancient Greek mythology. Until the early 1970s the nebula was believed to be a supernova remnant. In 1971, astronomers in the Soviet Union analyzed expansion velocities and thermal characteristics and determined that most likely it is a planetary nebula.
The image above was compiled from narrow band filtered exposures to create a mapped color depiction of the Nebula. A Bi-Color palette with Ha mapped to the red channel and OIII mapped to the green and blue channels was utilized. This mapping technique results in a Near True Color Image. A Hubble Palette (SII/Ha/OIII) version of the image may be viewed here.