Apianus’s depictions of Ursa Major and Ursa Minor
Ursa Major was visualized both as a horse-drawn cart and a bear in the two halves of this diagram in the Cosmographicus Liber of 1524 by Peter Apian (aka Petrus Apianus). On the left Ursa Major is called Plaustrum, the Latin name for a horse-drawn cart.
In his book Cosmographicus Liber of 1524 the German astronomer and mathematician Peter Apian (1495–1552), also known as Petrus Apianus, published this two-part diagram of the north polar region of the sky. On the left he depicted the great bear as a four-wheeled cart pulled by a team of three horses, the middle one with a rider. In the panel on the right the star that marks the rider is labelled Alcor, a name introduced by Apian on this chart.
The pole star is labelled Stella Polaris on the chart at left while on the right it is called Stella Maris, Latin for ‘star of the sea’, in reference to its role in navigation. On both sides of the diagram the constellations are drawn in reverse, as on a celestial globe.
A second edition of the book appeared in 1529, revised and edited by the Dutch mathematician and geographer Gemma Frisius (1508–55), who went on to produce many further editions of it. Gemma Frisius’s version contained a different diagram (below) in which the constellations are presented the right way round, as seen in the sky. Dotted lines indicate sighting lines to the north celestial pole.
Later editions of Apian’s book from 1529 onwards, edited by Gemma Frisius, replaced the original diagram with this one in which the constellations are drawn as seen in the sky.
