Carina is a constellation in the southern hemisphere. Its name means "keel" in Latin. Carina used to be a part of the constellation Argo Navis ("the ship Argo"), created by the Greek astronomer Ptolemy in the 2nd century, before Argo Navis was divided into three constellations – Carina (the keel), Puppis
(the stern) and Vela
(the sails) – by Nicolas Louis de Lacaille in the 18th century. Argo Navis represented Argo, the ship on which Jason and the Argonauts sailed to retrieve the Golden Fleece. The constellation was also sometimes associated with the ship that carried Menelaus home after the Trojan War. Egyptians also identified the constellation with a ship, one that carried Osiris and Isis during the big flood.
The constellation Carina occupies an area of 494 square degrees and contains seven stars with known planets. It can be seen at latitudes between +20° and -90° and is best visible at 9 p.m. during the month of March.
Carina contains a number of interesting objects to observe. First, there is the second brightest star in the sky, 
alpha Carinae or Canopus. Lying approximately 700 light-years from Earth, Canopus has a visual magnitude of -0.72, is more than 15,000 times more luminous than the Sun, and belongs to the rare class of F-type supergiants. To navigators living in the northern hemisphere, Canopus once served as the pole star. It cannot be seen from latitudes north of 37°18’.
Another interesting star is 
eta Carinae, a supermassive star in the Eta Carinae Nebula. Eta Carinae is also known as Foramen and Tseen She ("heaven’s altar") in China. It has more than 100 times the mass of the Sun and is really a multiple star system, one of the most massive ones that can be studied in detail. It contains at least two stars, one of them a blue variable star that is about four million times as luminous as the Sun and is expected to explode in a supernova within the next million years. When it does, it might affect the Earth’s upper atmosphere (the ozone layer) and any objects in it. In the late 19th century, a giant eruption was observed on eta Carinae that appeared as a supernova event, but the star survived. The supernova impostor event could have been either a surface instability or a failed supernova, presumably a result of built-up radiation pressure, and the star’s structure has still not fully recovered from it.
Two other notable stars are 
epsilon and 
upsilon Carinae, both binary stars that can be seen in small telescopes. 
epsilon Carinae, also known as Avior, has a magnitude of 1.86 and is one of the brightest stars in the sky, but cannot be seen from the northern hemisphere. Its primary component is a dying orange giant and the companion star is a blue dwarf. 
upsilon Carinae is part of the Diamond Cross asterism in the Carina constellation, together with 
theta and 
omega Carinae. The binary star’s primary component is a white supergiant and the companion is a blue-white giant.
With the Milky Way passing through Carina, there are many open clusters to observe in the constellation. The most interesting one is the Homunculus Nebula, an emission nebula surrounding 
eta Carinae, believed to have been ejected in the huge outburst from the star in 1841. Homunculus is part of the much larger Eta Carinae Nebula, or NGC 3372. Other than eta Carinae, NGC 3372 also surrounds several open star clusters as well as star HD 93129A, one of the most luminous stars in the Milky Way. HD 93129A is a blue O-type supergiant, a binary, about 7,500 light-years distant.
The Carina Nebula holds several O-type stars. It is about four times larger than the Orion Nebula. A part of it is known as the Keyhole Nebula, named by English mathematician and astronomer John Herschel in the 19th century. The Keyhole Nebula is about seven light-years in diameter and appears as a small, dark cloud of dust with contrasting bright filaments of fluorescent gas.
The Diamond Cluster or NGC 2516 got its name because it is so clear and easily visible even without a telescope. It holds two magnitude 5 red giants and three binary stars, as well as about a 100 stars that seem to be the same size as a full moon.
The Theta Carinae Cluster or IC 2602, better known as the Southern Pleiades, is another open cluster in Carina that can be seen with the naked eye. It has a magnitude of 1.9 and contains about 60 stars, including 
theta Carinae, a blue-white B-type main sequence dwarf.
NGC 2808 is a globular cluster that belongs to the Milky Way. It is one of the galaxy’s most massive clusters, consisting of more than a million stars.
Finally, NGC 3532 or the Wishing Well Cluster is an open cluster that got its name because, when observed through a telescope, it appears like many silver coins twinkling in a wishing well.
Carina belongs to the Heavenly Waters family of constellations, along with Delphinus
, Piscis Austrinus
Constellations directly bordering Carina are Vela