Ursa Major, the Great Bear

Nomenclature

• Latin: Ursa Major
• Genitive: Ursae Majoris
• Abbreviation: UMa
• Greek: Ἄρκτος Μεγάλη Arktos Megale
• Arabic: al-Dubb al-Akbar

All three versions of the name mean 'the greater bear' a translation of the original Greek name of Almagest. However, earlier sources simply called the constellation Ἄρκτος Arktos, and so the 'greater' epithet came later by comparison to the Phoenician Ursa Minor.

Description

Ursa Major is one of the most familiar constellations of the northern sky, and is a wonder to all those who view it. The stars of the Big Dipper (the Plough of the British Isles) comprise the rump of the bear and as well as the brightest and most recognisable figure of the night sky to many. Johann Bayer labelled the asterism's stars by right ascension rather than by magnitude, as was his usual ranking criterion.

The two brightest stars of the Big Dipper, Merak (β) & Dubhe (α) UMa, are also known as the Pointers, as a line drawn from Merak through Dubhe and continued onwards will eventually approach Polaris (α UMi), allowing one to easily locate the North Celestial Pole. Ursa Major is composed of many stars other than those of the Big Dipper, and as such is the third largest constellation by area of the night sky covered.

The two bears process throughout the northern sky, their muzzles pointed in the direction of each other's tails. Between them snakes the constellation Draco, and tailing Ursa Major is the constellation Boötes along with Canes Venatici, his hunting dogs.

Mythology

Callisto

Καλλιστώ Callisto was a nymph who underwent an unfortunate tale. According to Hesiod, she was born to King Lycaon of Arcadia and took a particular interest in hunting. She thus became a companion of Artemis, fashioning herself in the goddess's image by tying up her hair in a white ribbon, pinning her tunic with a brooch, and taking a vow of chastity, quickly becoming one of Artemis's favourites.

Zeus found her in the forest, resting while on hunt, and was completely smitten by her. Some tellings then say that he transformed into Artemis, approached her and, after laying down next to her, raped her. Other tellings omit his transformation. Callisto, ashamed at the breaking of her vow of chastity, hid the pregnancy from her compatriots. However, when the huntresses of Artemis bathed in a river to seek relief from the hunt, Callisto's pregnant belly was plain to see, and Artemis banished her from her party.

The transformation of Callisto into a bear goes by many tellings. Ps-Eratosthenes stated that when Artemis discovered her pregnant belly, she transformed her either because she broke her vow of chastity or because her beloved Callisto chose to hide the fact from her for so long. Amphis claimed that Callisto blamed Artemis for the pregnancy, not knowing that it was Zeus in Artemis's disguise that embraced her, angering Artemis and causing her to transform Callisto. Ovid in Book II of his Metamorphoses stated that it was instead Hera that transformed Callisto to spite Zeus for his affair. Apollodorus mentioned instead still that Zeus transformed Callisto to hide the affair from Hera. In the latter two tellings, Callisto was killed by Artemis who, unwittingly, was led to the bear by Hera. To mark his displeasure of the situation, Zeus then placed Callisto amongst the stars.

After being transformed into a bear, Callisto gave birth to her son by Zeus, named Arcas. In a recounting by Ps-Eratosthenes, a group of goatherds found the bear-formed Callisto and her son in the woods and brought them to Lycaon as a gift. Ignorant of the law prohibiting entry onto the premises of the temple of Lycaean Zeus, Callisto trespassed on the temple with Arcas in tow. Angered, the Arcadians formed a mob and sought to kill them. In their moment of desperation, Zeus, reflecting on the pain he had caused Callisto, rescued his mistress and son by placing them into the sky, Callisto as Ἄρκτος Arctos, 'the bear', and Arcas as Ἄρκτοφυλαξ Arctophylax, 'bear warden, or watcher' (see Boötes). In another recounting by Ps-Eratosthenes, he instead stated that Lycaon, angered by Zeus's violation of his daughter, invited the King of the Gods to a banquet where he served a butchered Arcas along with other animal meats. Enraged, Zeus flipped the table over and blasted Lycaon's home with a lightning bolt, transforming Lycaon into a wolf and remaking Arcas. Zeus then gave his son either to a goatherd or to the Pleid Maia to be raised in the wilds of Arcadia. In his later years, Arcas happened upon his mother on a hunt and pursued her into the temple of Lycaean Zeus, where the pair met the same fate as in the aforementioned story.

Regarding the circumpolarity of Ursa Major (to the ancient Greeks), Hyginus recounted the telling that Tethys and Oceanus, nurses of Hera, did not allow Callisto to touch the ocean on account of her sleeping with the husband of their foster child.

By some accounts, Callisto went by the alternative name Megisto, and instead of having Lycaon as her father had Ceteus, son Lycaon. In the telling of Araethus of Tegea, Ceteus was pictured in the sky as the Kneeler (see Hercules), lamenting his daughter's transformation.

Helice

According to Aratus in his Phaenomena, Ursa Major was named Ἑλικη Helice, an Idaean nymph and nurse of Zeus. She and her sister Κυνόσουρα Cynosura were tasked by Rhea with the nursing of the infant Zeus and protection from his cannibalistic father Cronus, a task which they accomplished with the help of the Κουρητες Curetes, whose clashing of shield and spear masked the infant's wails, and the she-goat Αμαλθεια Amalthea, who suckled the infant. Since they fed him honey, the nymphs were also known as Μελιαι Meliai, '[nymphs] of honey'.

On one particular day, Cronus happened upon Mount Dicte in Crete where the nymphs were nursing Zeus in search of his uneaten son. Zeus then transformed himself into a dragon and Cynosura and Helice into bears, deceiving his father and allowing the trio to live another day. After the Titanomachy, to honour their rearing of him, Zeus placed his nurses in the sky, Cynosura as the Lesser Bear and Helice as the Greater Bear, flanking himself as the Dragon.

The names Cynosura and Helice likely derive from astral association rather than by mythological association. Cynosura is from Greek, meaning 'dog's tail', alluding the shape Ursa Minor. Helice is also from Greek, meaning 'the one that circles', alluding to Ursa Major's circumpolar motion across the northern sky.

Hamaxa and Septentrio

The stars of the Big and Litte Dippers were referred to as Ἄμαξα Hamaxa, 'wain, or wagon', by Aratus. However, the title was likely originally only for the stars of the Big Dipper. This is because these stars precede the Ox-Driver constellation Boötes, and by association with that figure were imagined as two oxen, Merak (β) & Dubhe (α) UMa, pulling the cart composed of the other five stars of the Big Dipper. While Germanicus Caesar still called the figure a plough, in Roman times the figure had evidently also shifted to that of Septentrio, 'seven plough-oxen', as recorded by Hyginus. As such, the word "septentrional" gradually became synonymous with "northerly".

Stars

Sources