In modern astronomy, a constellation is a clearly defined area of the sky. Historically however, the term was also used to refer to a perceived pattern formed by bright stars with apparent proximity to one another, and this practice is still common today. The 48 ancient Graeco-Roman constellations were named after mythological heroes, while the 40 newer ones (mostly from the southern hemisphere) have been named after scientific instruments and animals.
Today the sky is divided in 88 constellations of various sizes. They can be grouped into constellation families which are groups of constellations from the same region of the celestial sphere.
Ursa Major Family:
The Ursa Major Family is a group of 10 constellations located around the north celestial pole. It includes the constellations of Ursa Major, Ursa Minor, Draco, Canes Venatici, Boötes, Coma Berenices, Corona Borealis, Camelopardalis, Lynx, and Leo Minor.
The Zodiac is a group of 12 constellations through which the ecliptic and the apparent motion of the Sun pass throughout the year. It includes the famous constellations of Leo, Virgo, Libra, Scorpius, Sagittarius, Capricornus, Aquarius, Pisces, Aries, Taurus, Gemini, and Cancer. These 12 constellations have zodiac signs. However, the sun and the ecliptic also pass through the constellation of Ophiuchus which has been omitted from the zodiac, and therefore does not have a sign.
The Perseus Family is a group of 9 constellations composed of Cassiopeia, Cepheus, Andromeda, Perseus, Pegasus, Cetus, Auriga, Lacerta, and Triangulum. It spans from near the north celestial pole down to –30° and the spring meridian crosses this family.
The Hercules Family is a group of 19 constellations composed of Hercules, Sagitta, Aquila, Lyra, Cygnus, Vulpecula, Hydra, Sextans, Crater, Corvus, Ophiuchus, Serpens, Scutum, Centaurus, Lupus, Corona Australis, Ara, Triangulum Australe, and Crux. It is the largest constellation family, spanning from +60° down to –70°, mostly in the western hemisphere.
Orion Family is the smallest group. It includes 5 constellations: the famous Orion as well as Canis Major, Canis Minor, Monoceros, and Lepus.
The Heavenly Waters is a group of 9 constellations composed of Delphinus, Equuleus, Eridanus, Piscis Austrinus, Carina, Puppis, Vela, Pyxis, and Columba. These constellations are associated with aquatic creatures. The constellations of Carina, Puppis, and Vela are parts of the former constellation Argo Navis.
The Bayer Family is a group of 11 constellations introduced by Johann Bayer in 1603 (hence the name of the family). They are located in the far southern sky and therefore were not visible for the ancient Greeks and Romans. The family includes the constellations of Hydrus, Dorado, Volans, Apus, Pavo, Grus, Phoenix, Tucana, Indus, Chamaeleon, and Musca.
La Caille Family:
The La Caille Family is a group of 13 constellations composed of Norma, Circinus, Telescopium, Microscopium, Sculptor, Fornax, Caelum, Horologium, Octans, Mensa, Reticulum, Pictor, and Antlia. These constellations were introduced by Nicolas Louis de Lacaille in 1756 (hence the name). Just like the Bayer Family these constellation are located in the far southern sky and were not visible for the ancient Greeks and Romans.
Alphabetical List of the Constellations:
Andromeda · Antlia · Apus · Aquarius · Aquila · Ara · Aries · Auriga · Boötes · Caelum · Camelopardalis · Cancer · Canes Venatici · Canis Major · Canis Minor · Capricornus · Carina · Cassiopeia · Centaurus · Cepheus · Cetus · Chamaeleon · Circinus · Columba · Coma Berenices · Corona Australis · 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