German astronomer who in 1647 published the first comparatively detailed map of the Moon in his Selenographia. He also discovered four comets and suggested that these bodies orbited in parabolic paths about the Sun.

Hevelius was born in Danzig (now Gdask). He worked as a brewing merchant and was a city councillor, but spent his evenings on the roof of his house, where he had an observatory installed 1641. This was destroyed by fire in 1679, with some of his notes. His wife Elizabeth assisted him in his work and, after his death, she edited and published his Prodromus astronomiae 1690.
Between 1642 and 1645, Hevelius deduced a fairly accurate value for the period of the solar rotation and gave the first description of the bright areas in the neighbourhood of sunspots. The name he gave to them, faculae, is still used.
Although Hevelius used telescopes for details on the Moon and planets, he refused to apply them to his measuring apparatus, and his observations of the positions of stars were made with the naked eye, not always accurately. His Uranographia 1690 contains a catalogue of more than 1,500 stars and a celestial atlas with 54 plates.