Hevelius and second wife Elisabeth observing the sky with a brass sextant. To Hevelius, telescopes were for making discoveries, not measurements, says historian Albert Van Helden, professor emeritus at Rice University in Texas and Utrecht University in the Netherlands. While Hevelius made use of telescopes to map the moon, the astronomer charted the positions of stars without using one.

Nonetheless, a small number of names Hevelius gave to lunar characteristics are still in use today-such as “Alps” for lunar mountains. Such names were replaced largely by the efforts of Giambattista Riccioli and Francesco Maria Grimaldi who collaborated on topographical maps of the moon published in 1651. Thus, there were continents, islands, seas, bays, rocks, swamps, marshes and so on. However, most of his names for lunar characteristics have fallen out of favor because his names were based on Earth's geography. Hevelius also named dozens of features across the lunar landscape. Hevelius's 150 feet focal-length telescope. Hevelius published them under the name Selenographia. Together they represents the first detailed, accurate maps of the moon's surface. At the end of five years, he had produced some 40 engraved plates. Hevelius continued mapping the moon, producing copper engravings of every sketch he made. “You are gifted with such superior eyes, which one could really call the ‘eyes of a Lynx,’” Gassendi wrote. When Hevelius sent his drawings to Peter Gassendi, a friend and fellow astronomer based in Paris, Gassendi was so impressed by Hevelius’s work that he implored his friend to continue the project. Peering through the telescope trained towards the natural satellite, Hevelius spent countless nights producing drawings of the moon’s surface, just like Galileo had four decades earlier, only Hevelius’s quality of work far surpassed that of the Italian astronomer. One of Hevelius’s first major undertakings was mapping of the moon. His observatory was visited by many dignitaries, such as the Polish King John III Sobieski and English astronomer Edmond Halley. The observatory was known by the name Sternenburg or “Star Castle”, and it became one of the greatest observatories in Europe at the time. He filled this observatory with splendid instruments, ultimately including a large Keplerian telescope of 150 feet focal length. In 1641, Hevelius constructed an observatory on the rooftops of three adjoining houses that he owned in Gdańsk. He returned to Gdańsk in 1634 and became a brewer himself, but his mathematics teacher, Peter Krüger, managed to inspire young Hevelius in astronomy. At the age of 19, Hevelius went to study law at the University of Leiden. His father owned a profitable brewery and wanted his son to become a businessman like himself. Johannes Hevelius was born in 1611 in Danzig, Poland. The surface of the Moon by Johannes Hevelius. He produced the first detailed map of the moon documenting every crater, slope and valley that he could see with his telescope. However, it was through the use of telescopes that Hevelius gained fame as “the founder of lunar topography”. It was the most comprehensive celestial atlas of its time. With the aid of only a quadrant and an alidade, Hevelius compiled a catalog of more than fifteen hundred stars with unprecedented accuracy.

German astronomer Johannes Hevelius is often regarded as one of the last great astronomers to carry out major observational work without a telescope.

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