Johannes Hevelius (in German also known as Hevel; Polish: Jan Heweliusz; 28 January 1611 – 28 January 1687) was a councillor and chairman of the city council of the Old Town, Gdańsk (in the Polish–Lithuanian Commonwealth). As an astronomer, he gained a reputation as "the founder of lunar topography", and described ten new constellations, seven of which are still used by astronomers.