M57 — Ring Nebula
Planetary Nebula in Lyra
About
A planetary nebula in Lyra, about 2,570 light-years away: a shell of gas shed by a dying star. The central star is now a white dwarf of about 0.6 solar masses at roughly 125,000 K. The shell is about one light-year across.
Imaging tips
- Only about 1.4′ by 1′, so it is too small to frame: use a long focal length and a fine pixel scale.
- The bright ring can drown the faint outer gas. One imager's 3 hours of 6-minute subs chose to show the ring and give up the halo.
- Bringing out the outer Hα halo took long data: 12 hours, 8 of them Hα in 10-minute subs, with the core masked while the halo was stretched.
- The inner ring glows blue-green in O III and the outer zone red in hydrogen and nitrogen, so O III plus Hα separates them.
- Best in June and July.
Facts
- Size
- 1.4′ × 1′
- Magnitude
- 8.8
- Coordinates
- RA 18h 53.6m, Dec +33° 2′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Jun, Jul
- Peak altitude
- 73° from 50°N, 88° from 35°N