M46 (Open Cluster) & NGC 2438 (Planetary Nebula)
A rich open cluster in Puppis that appears to host the planetary nebula NGC 2438 (which is likely a foreground object). The cluster is a binocular target, while the PN needs a telescope and possibly filters.
Open cluster in Puppis. Magnitude 6.1 (the cluster).
Can you see it from Guyana?
From Georgetown (6.8° N) it climbs to 68° above the southern horizon at its highest; from Lethem (3.4° N), to 72° above the southern horizon. It is highest at midnight on the night of 13 Jan, in the middle of its season. The page works out tonight's rise, highest point and set for both towns in Guyana time (UTC-4), and where the Moon is.
What you'll see
- Your eyes: Not visible to the eye.
- 10x50 binoculars: Resolves into dozens of stars.
- A small telescope (80 to 100 mm): A rich cluster of faint stars, with the small planetary nebula NGC 2438 on its edge (an OIII filter helps).
- A camera: Spans about 40% of an APS-C frame at 1,000 mm (field 1.3° × 0.9°); needs a tracking mount.
How big, how bright, how far
- Size on the sky: 27′, 87% of the Moon's width (the Moon is about 31′ wide).
- Brightness: magnitude 6.1. Fainter than the faintest stars in Georgetown (4.3) and Lethem (6.0): binoculars or a telescope.
- Distance: 5,070 light-years. The light reaching your eye left it about 5,100 years ago.
What it is made of
- Type
- Open cluster
- Distance
- Approx. 5,070 Lightyears
- True size
- Approx. 40 Lightyears across
- Age
- about 430 million years (range 270 million years to 690 million years)
- Notable
- The planetary nebula NGC 2438 on its edge is not part of the cluster: it lies much closer (Gaia parallax 1.38 ± 0.22 mas, about 2,400 light-years, against the cluster's 5,070).
More deep-sky objects: M47 (Open Cluster) · M93 (Open Cluster) · M41 (Open Cluster) · Christmas Tree Cluster & Cone Nebula (NGC 2264) · M67 (Open Cluster) · Beehive Cluster (M44)