Exhibit of the Month

February 2020

Astronomicum Caesareum
NK CR, shelf mark 14 A 1

The greatest work of German astronomer, mathematician, cartographer and publisher Peter Apian (1495-1552) is Astronomicum Caesareum, made and published by his own printing  workshop in Ingolstadt in 1540. It is estimated that around one hundred copies have been preserved, which is a substantial part of the original edition. This beautiful hand-coloured book (each copy is an original thanks to various colours used for colouring) is considered to be the most beautiful astronomical publication.  In 1967, its facsimile was published in Leipzig in the edition of 750 copies. The first two hundred of them were numbered and coloured.

The National Library of the CR keeps in its collections two copies of the original print from 1540 and the facsimile from Leipzig Nr. 173.

Through his graphic work, Peter Apian wanted to  make astronomy easier for understanding.  For this purpose he used his illustrative multi-layer rotating depictions instead of complicated calculations and tables. Astronomy in his times was excessively mathematically complicated, because it was based on the idea that the centre of the Universe is the Earth. This erroneus geocentric assumption made the calculations extremely complicated. At that time, Nicolaus Copernicus (1473-1543) had already calculated his heliocetric model but it was published in print under the title Nicolai Copernici Torinensis de revolutionibus orbium coelestium Libri VI. as late as 1543.

Digitized Astronomicum Caesareum by Peter Apian can be viewed and downloaded (in monochrome or colour version, in various resolutions) at https://www.univie.ac.at/hwastro/rare/1540_apian.htm.