Often overlooked due to its faintness, SH2-221 is a supernova remnant nestled within the constellation Auriga, roughly 2,600 light-years away. This ethereal structure spans nearly 1.5 degrees across the sky—about three times the size of the full Moon—yet it remains challenging to observe due to its diffuse nature and low surface brightness. The glowing filaments and arcs visible in this deep image are composed primarily of ionized hydrogen gas, remnants of a star that exploded thousands of years ago.

Captured from Gualdo Tadino in Perugia, Italy, this image reveals the delicate and ghostly outlines of SH2-221 set against a richly textured star field. Long exposure and narrowband filters help isolate the nebula’s faint emission from the background, allowing the structure to emerge in dramatic detail. Observations like these continue to shed light on the dynamic processes that shape the interstellar medium long after a star’s explosive death.

Image Description and Details : This is a 4 panel mosaic done over multiple nights and requiring more than 120 hours. It was captured from Andalusia in Spain using a AP130GTX refractor on top of a 10Micron mount.
The colour scheme is HSO with added RGB stars. The following frames were captured :
- Ha : 244 X 600s
- OIII : 220 X 600s
- Sii : 220 X 600
- RGB : for each 60 X 180

Copyright: F Drevon