Cancer (abbr. Cnc, gen. Cancri)
Cancer. © 2003 Torsten Bronger.
The constellation of Cancer represents the Crab sent by Juno to save the Hydra in its battle with Hercules but unfortunately crushed underfoot during the ensuing melee. It is a dim northern constellation (shaped a bit like Orion) and the fourth sign of the zodiac, located between Castor and Pollux of Gemini and Regulus of Leo.
In former times the Sun used to lie in Cancer when it reached its point farthest north – the time of the summer solstice – but today, because of precession, the Sun passes through Cancer from late July to early August.
X Cnc is a semi-regular variable with a striking red color and an easy object with binoculars (magnitude range 5.6 to 7.5; period 195 days; R.A. 8h 55.4m, Dec. +17° 14'). Cancer also contains the open clusters Praesepe (M44) and M67 (NGC 2682). The latter has at least 200 stars and is best seen through larger telescopes (magnitude 6.9; diameter 30'; R.A. 08h 50.4m, Dec. +11° 49'. See below for details of the constellation's brightest stars.
|Stars brighter than magnitude 4.0|
|R.A. (h m s)||Dec. (° ' '' )|
|Beta (Altarf)||3.53||0.14||K4IIIBa0.5||290||08 16 31||+09 11 08|
|3.94||0.83||K0III-IIIb||136||08 44 41||+18 09 15|
|Andromeda | Antlia | Apus | Aquarius | Aquila | Ara | Aries | Auriga | Bootes | Caelum | Camelopardalis | Cancer | Canes Venatici | Canis Major | Canis Minor | Capricornus | Carina | Cassiopeia | Centaurus | Cepheus | Cetus | Chamaeleon | Circinus | Columba | Coma Berenices | Corona Austrina | Corona Borealis | Corvus | Crater | Crux | Cygnus | Delphinus | Dorado | Draco | Equuleus | Eridanus | Fornax | Gemini | Grus | Hercules | Horologium | Hydra | Hydrus | Indus | Lacerta | Leo | Leo Minor | Lepus | Libra | Lupus | Lynx | Lyra | Mensa | Microscopium | Monoceros | Musca | Norma | Octans | Ophiuchus | Orion | Pavo | Pegasus | Perseus | Phoenix | Pictor | Pisces | Piscis Austrinus | Puppis | Pyxis | Reticulum | Sagitta | Sagittarius | Scorpius | Sculptor | Scutum | Serpens | Sextans | Taurus | Telescopium | Triangulum | Triangulum Australe | Tucana | Ursa Major | Ursa Minor | Vela | Virgo | Volans | Vulpecula|