NGC 2438 [SEP] constellation
NGC 2438
NGC 2438 is a planetary nebula about 3,000 light years away in the constellation Puppis. It was discovered by William Herschel on March 19, 1786.
NGC 2438 appears to lie within the cluster M46, but it is most likely unrelated since it does not share the cluster's radial velocity. The case is yet another example of a superposed pair, joining the famed case of NGC 2818.
Long exposures have shown that this planetary nebula has an extended double halo, while the more easily visible portion probably
, NGC 2438 is a larger object in the background. 
External links.
- PIA04228: Rotten Egg Nebula, NASA Planetary Photojournal
- The Rotten Egg Planetary Nebula, APOD 1999 November 1
- The Making of the Rotten Egg Nebula, APOD 2001 September 3
- Calabash Nebula at Constellation Guide
- Calabash Nebula imaged and interpreted by Bo Reipurth at the European Southern Observatory in 1987