M33 — Triangulum Galaxy
Galaxy in Triangulum
About
The Triangulum Galaxy, a spiral galaxy about 2.9 million light-years away, about 61,000 light-years across and the third-largest member of the Local Group. It holds NGC 604, one of the largest star-forming regions known.
Imaging tips
- About 73′ × 45′: 330–550 mm on APS-C or 510–850 mm on full frame spans a third to half of the frame; one imager found about 800 mm fits the galaxy well.
- One guide advises subs of 5 minutes or more to catch faint detail; another stack used 84 × 5 min (7 h) from a modified DSLR.
- Low surface brightness at 23.1 mag/arcsec² despite magnitude 5.7; single subs show the core but little arm structure until stacked.
- Galactic Hunter's 2024 collaboration combined LRGB with H and O data; the hard part is showing the arms without overprocessing. Best September to November.
Facts
- Size
- 73′ × 45′
- Magnitude
- 5.7
- Coordinates
- RA 1h 33.8m, Dec +30° 40′
- Framing, APS-C
- 330–550 mm
- Framing, full frame
- 510–850 mm
- Best months
- Sep, Oct, Nov
- Peak altitude
- 71° from 50°N, 86° from 35°N