H-NGC2438 — M46 Planetary
Planetary Nebula in Puppis
About
In Puppis, NGC 2438 is a double shell of gas shed by a dying star (a planetary nebula), whose bright 60″ core sits inside a fainter halo near 130″. Gaia puts it about 1,370 light-years away. It appears inside M46 but is unrelated, since its velocity differs from the cluster's.
Imaging tips
- Far too small to frame: it needs a long focal length and a fine pixel scale. It lies roughly 4.5–5′ (approximate, from coordinates) from the centre of the 27′ cluster M46, so a wider frame shows both.
- It is bright for its size, and one imager advised protecting the core from overexposure and keeping the colours accurate through processing.
- That image used 3 hours of 5-minute subs on an unfiltered one-shot colour camera.
- A narrowband project used 24 × 40 min of Hα and 22 × 40 min of OIII, part of a 32-hour total, to show very faint outer shells.
- Best in January; it peaks near 25° from 50°N.
Facts
- Size
- 1′
- Magnitude
- 10.8
- Coordinates
- RA 7h 41.8m, Dec −14° 44′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Jan
- Peak altitude
- 25° from 50°N, 40° from 35°N