In the Roman era, the celestial pole was about equally distant between Polaris and Kochab. 320 BC described the celestial pole as devoid of stars. However, at magnitude 3.67 (fourth magnitude) it is only one-fifth as bright as Polaris, and today it is invisible in light-polluted urban skies.ĭuring the 1st millennium BC, Beta Ursae Minoris ("Kochab") was the bright star closest to the celestial pole, but it was never close enough to be taken as marking the pole, and the Greek navigator Pytheas in ca. In 3000 BC, the faint star Thuban in the constellation Draco was the North Star, aligning within 0.1° distance from the celestial pole, the closest of any of the visible pole stars. ĭue to the precession of the equinoxes (as well as the stars' proper motions), the role of North Star has passed (and will pass) from one star to another in the remote past (and in the remote future). The celestial pole will be nearest Polaris in 2100 and will thereafter become more distant.
Therefore, it always appears due north in the sky to a precision better than one degree, and the angle it makes with respect to the true horizon (after correcting for refraction and other factors) is equal to the latitude of the observer to better than one degree. "Cynosure, or the Marian Polar Star"), a collection of Marian poetry published by Nicolaus Lucensis (Niccolo Barsotti de Lucca) in 1655. Īn explicit identification of Mary as stella maris with the North Star ( Polaris) becomes evident in the title Cynosura seu Mariana Stella Polaris (i.e. The name stella polaris was coined in the Renaissance, even though at that time it was well recognized that it was several degrees away from the celestial pole Gemma Frisius in the year 1547 determined this distance as 3☈'. In the Vishnu Purana, it is personified under the name Dhruva ("immovable, fixed"). It was known as scip-steorra ("ship-star") in 10th-century Anglo-Saxon England, reflecting its use in navigation. The ancient name of Ursa Minor, anglicized as cynosure, has since itself become a term for "guiding principle" after the constellation's use in navigation.Īlpha Ursae Minoris (Polaris) was described as ἀειφανής (transliterated as aiphanes) meaning "always above the horizon", "ever-shining" by Stobaeus in the 5th century, when it was still removed from the celestial pole by about 8°. While there was no naked-eye star close to the pole, the midpoint between Alpha and Beta Ursae Minoris was reasonably close to the pole, and it appears that the entire constellation of Ursa Minor, in antiquity known as Cynosura (Greek Κυνόσουρα "dog's tail") was used as indicating the northern direction for the purposes of navigation by the Phoenicians. In classical antiquity, Beta Ursae Minoris (Kochab) was closer to the celestial north pole than Alpha Ursae Minoris. The path of the south celestial pole among the stars due to the effect of precession