The planetary nebula NGC 2438 in NGC 2437 (M46)
AAO image reference AAT 107. « Previous || Next »
The open cluster NGC 2437 (M46) has an angular diameter of almost half a degree and is quite beautiful in even quite a modest telescope. It has an integrated magnitude of about 6 and so is on the threshold of naked-eye visibility. Because M46 almost fills the field of view here, the cluster is not obvious. It is quite old as these things go, about 300 million light years. It is about 5000 light years distant, in the northern part of the constellation of Puppis. Though planetary nebula distances are notoriously difficult to measure, NGC 2438 seems to be in the foreground and is not connected to the cluster. Planetaries are in any case the result of the demise of an old, low mass stars and are thus not seen in relatively young open clusters.
Top left is NE. Image width is about 31 arc min
Image and text © 1993-2010, Australian Astronomical Observatory, photograph by David Malin.
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