The constellation Puppis is part of a whole group of constellations that represents various parts of the good ship Argo, made famous by its crew, Jason and the Argonauts. These particular stars are the ass end of that ship, i.e. the poop deck.
Although the poop deck is in back, it isn’t actually where sailors poop (excuse my french). That happens at the front end of the ship, the “head” which is why you may have occasionally heard the bathroom called a head. I assume all the smelly business was done at the front of the ship because with sailing vessels that is generally the way the wind is blowing. Meanwhile the French word for “stern” is “la poupe” so there you go.
There are three Messier open clusters in Puppis, M46, M47, and M93. Open clusters are young families of related stars born somewhat recently, and still waiting to try their wings and leave the nest. But if you look close at M46 you’ll see an anomaly, the planetary nebula NGC 2438. A planetary nebula is the gassy shroud surrounding an old timer, a star with one foot in the grave and the other on a banana peel. In this case the planetary is just photo-bombing the cluster. It is much closer to us than the stars of M46 and not even headed in the same direction.
Here’s the deal on all the “M” objects. In the 1700’s Charles Messier created a list which is the all cool things to show people who are wondering why the hell you spent so much money on a telescope. There are somewhere between 108 and 110 objects on Messier’s list depending on who you ask because his notes and methods were less than perfectly organized. But if you join a local Astronomical League club, those geeks will get strangely happy if you swear you found them all. They’ll give you a special geeky pin to wear and a certificate. Basically it proves that you are easily excited by seeing faint wisps of light that are barely visible.
After you have achieved such honor and distinction, you may want to go on to tackle the Herschel objects. If the Messier program is like earning a Cub Scout merit badge, then the Herschel program is like joining the Marine Corps. William Herschel had a much bigger telescope and discovered thousands of objects way wispier than the Messiers. The Astronomical League has listed 400 objects for the program and they are kind of picky about how you log your observations in order to get the pin and certificate. I found most of my Messiers in one night. It took me six years to finish my Herschels.
Here is a Link to my Herschel Log. Semper Fi.
If you decide to log all the Messiers, and you get around to observing the open cluster M46 in Puppis, you can’t help but find that pesky foreground interloper, planetary nebula NGC 2438. It just happens to be one of the Herschel objects. So log that little bugger too and you’ll be well on your way to elevating your street cred in the glorious star-hopping geeky subculture of astronomy.