M101 · Pinwheel Galaxy
| Chinese name | 风车星系 |
|---|---|
| Type | Galaxy |
| Constellation | UMa |
| RA | 14h03m |
| Dec | +54° |
| Apparent magnitude | 7.9ᵐ |
| Hemisphere | Northern |
| Best season | Spring |
| Difficulty | Moderate |
| Focal length | 中焦 600–1000mm |
About
The Pinwheel Galaxy lies about 21 million light-years away in Ursa Major, about 170,000 light-years across, a giant face-on spiral noticeably larger than the Milky Way. Its slightly asymmetric arms—likely shaped by interaction with nearby galaxies—are dotted with many bright giant H II regions such as NGC 5471, glowing as vivid pink stellar nurseries. Its large apparent size, decent surface brightness and rich detail let a medium focal length capture a spectacular full view. In May 2023 amateur astronomers discovered the supernova SN 2023ixf in one of its arms, briefly making it a focus of worldwide attention. It is one of the most rewarding spiral galaxies of the northern spring sky.