The Little Bear was once called the 'dog's tail'
Ursa Minor, home of the North Star, carried an odd ancient nickname: Cynosura, Greek for dog's tail. Nobody knows why, since no neighbouring constellation was ever a dog. One tradition made Cynosura a mountain nymph who nursed the infant Zeus; another proposal traces the word to an Assyrian phrase meaning high-rising.
Babylonian catalogues called it the Wagon of Heaven, listing it around 1000 BC among the Stars of Enlil, the northern sky. Greek writers claimed Thales of Miletus urged sailors to steer by it, as Phoenician mariners already did, which is why it was also called the Phoenician Bear. The Greeks themselves had been using the larger bear. The Latin word for north, septentrio, comes from seven oxen pulling a plough, a picture drawn from its seven stars.
The pole star has shifted over time. In classical antiquity the celestial pole lay nearer Beta Ursae Minoris, called Kochab, than Alpha, so the whole constellation served to mark north. Only from the medieval period did Polaris take over, and even then it sat several degrees off the pole; today it lies within 1 degree. The name stella polaris dates only from the early modern period. Inuit astronomers called Polaris, Kochab and Pherkad 'never moving', though at far northern latitudes the pole star rides too high to help with navigation.
Polaris, a supergiant with a yellow-white hue, is the night sky's most brilliant Cepheid variable, flickering between magnitudes 1.97 and 2.00. Kochab, an ageing orange giant, is barely fainter; with Gamma it forms the 'Guardians of the Pole'. Four of the constellation's stars host known planets. It also holds a lone neutron star, Calvera, and H1504+65, a white dwarf blazing at 200,000 kelvin, the second hottest found.
Covering 256 square degrees, Ursa Minor ranks 56th in size. The Little Dipper's bowl is handy for testing a sky's darkness, since its four stars descend neatly from second to fifth magnitude; seeing all four means fifth-magnitude stars are visible.
Source: Ursa Minor
