1647. The Selenographia of Johannes Hevelius

In 1643, as Johannes Hevelius started his first observations of the Moon, other astronomers were already on the same task several years before. This is the case for Michael van Langren (1598-1675), a Dutch cartographer, he is about to publish the first map of the Moon with a nomenclature. It was an ambitious project under the support of the Spanish monarchy. Unfortunately, in 1634, Van Langren learns the death of Queen Isabella of Austria, aunt of Philip IV of Spain, who was financially supporting the project. With no monetary support, but eager to be the first to publish a complete map of the Moon, Van Langren managed to have his work engraved and printed in 1645.

Michael van Langren, Plenilunii Lumina austriaca Philippica, 1645.

Two years later, in 1647, Johannes Hevelius published his Selenographia. On this occasion, money is not an issue as he was the son of a wealthy brewing merchant from Gdańsk (Dantzig), where a large observatory is located.

Johannes Hevelius, Selenographia, 1647.

The Selenographia is a remarkable work in a scientific and formal point of view. Hevelius is not only an astronomer, but also a draughtsman and engraver. By earning a helping hand from Jeremiah Falk (1610-1677) in this colossal enterprise, he created most of the engravings from the work. Highlighting the lunar libration, Hevelius demonstrate the possibility to map some craters located on the upper region of its visible side.[1] The astronomer also represents the different phases of the Moon, playing with the craters’ shadows, which allows him to position himself by following Galileo’s and Fontana’s footsteps; he somehow surpasses with his precise observations.

Hevelius proposed a new lunar nomenclature, which does not take into account Van Langren’s nomenclature.