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Johannes Hevelius

Johannes Hevelius

Hevelius, Johannes (1611–1687)

Polish astronomer, born in Gdansk, who established his name by recording his studies of the Moon’s surface. Johannes Hevelius studied Law at Leiden in 1630, after that he spent the years 1632–1643 making trips to Switzerland, London, and Paris, where he got to know several astronomers, together with Pierre Gassendi (1592–1655). In 1634 he came back to Gdansk to carry on his Law studies while supporting his family by helping with the family business. It was in 1639 when he thought of building his private observatory in his home place and dedicating himself to astronomy. Hevelius was also subsidised by the Polish King Jan III Sobieski (pension). He passed away on January 28, 1687.

Johannes Hevelius discovery and works include:
- the solar rotation period,
- report of the bright patterns in the area of sunspots (so called “faculae”),
- observations of the planets, particularly Jupiter and Saturn,
- confirmation of Copernicus (another famous Polish astronomer) predictions of Mercury which goes through phases,
- reports of lunar map,
- he discovered 4 comets which were called by him “pseudo-planetae”.