Welcome to our complete guide to the night sky’s 88 star constellations. Here you will learn what exactly constellations are, how they got their names, and how to identify and locate them when out stargazing.
What are constellations?
A constellation is simply a collection of stars, imaginatively linked together to represent a person, animal, or object in the night sky. In this way, astronomers are better able to organize the heavens into some recognizable form and make locating stars and other astronomical objects easier.
In 1922, the International Astronomical Union (IAU) recognized 88 modern constellations, 48 of which are based upon those recorded by the Greek astronomer Ptolemy around 150 AD in his treatise called ‘Almagest’.
How the constellations got their names
Many of the constellations in use today represent characters from Greek and Roman mythology. These ancient civilizations believed their gods dwelt in the celestial heavens, and so naturally looked for and found those deities in the pattern of the stars. As well as naming constellations after their gods, many mortals who had done something heroic got to live in the skies too, along with some of the creatures and objects associated with their legends. Out of all the recognized 88 constellations, 42 depict animals, 29 relate to objects, while 17 portray humans or mythological characters.
Star Constellation Families
The location of many different constellations in the night sky is important, as together with some of their neighbors, they often recount stories from the world of legend. Likewise, constellation families refer to groupings of constellations within the same region of the night sky, some of which also share some kind of ancient mythological relationship.
Of the eight constellation families, Hercules (19) contains the most constellations, followed by La Caille (13), Bayer (11), the Zodiac (12), Ursa Major (10), Perseus (9), Heavenly Waters (9), and Orion (5).
Zodiac is a Greek word meaning “pertaining to animals,” with the zodiac constellations included in the overall list of 88 constellations. The 12 traditional signs of the zodiac occupy an 18° wide band of sky centered on the ecliptic plane, which is the path the Sun, Moon, and planets seem to travel in the sky throughout the year. Naturally, this 360° ring marks the line along which any solar eclipse will also be seen to occur, and hence its name.
Throughout the year, the Sun appears in front of each zodiac constellation for a month or so, but as this takes place during our daytime, the view is obscured from view. If we could see the occurrence, we would observe the Sun slowly drifting in an easterly direction onto a different zodiac constellation as it continues its annual journey across the sky.
The 12 zodiac signs are as follows: Capricornus, Aquarius, Pisces, Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, and Sagittarius. In astronomy, there is also another constellation that intersects the ecliptic called Ophiuchus (serpent-bearer), which is sometimes referred to as the 13th zodiac sign.