M33 · Triangulum Galaxy
| Chinese name | 三角座星系 |
|---|---|
| Type | Galaxy |
| Constellation | Tri |
| RA | 01h34m |
| Dec | +30° |
| Apparent magnitude | 5.7ᵐ |
| Hemisphere | Northern |
| Best season | Autumn |
| Difficulty | Easy |
| Focal length | 中焦 400–800mm |
About
The Triangulum Galaxy lies about 2.7 million light-years away, the third-largest member of the Local Group after Andromeda and the Milky Way. It is nearly face-on, its sprawling arms studded with pink H II regions, including giant NGC 604, one of the largest star-forming regions in the Local Group at nearly 1,500 light-years across. It may be gravitationally linked to Andromeda and is faintly visible to the naked eye under dark skies. Its low surface brightness and large angular size demand dark skies and long exposures. Deep mid-focal-length imaging captures gorgeous stellar nurseries and blue clusters, making it highly rewarding.