In the Prodromus, Hevelius explained the instruments and methods used to produce the star catalog. Hevelius’ Gdansk observatory, “Stellaburg,” was the best in Europe until the later national observatories of France and Britain. Inspired by Tycho Brahe, he constructed large precision observing instruments, including a great sextant for measuring the angular distance of any star from nearby reference stars. In the frontispiece to the Prodromus, Hevelius joins the table of Urania, the Muse of astronomy, around which are seated a select number of great figures in the history of astronomy: Ptolemy; Tycho Brahe; Ulugh Beg; Henry of Langenstein (Landgrave of Hesse); and Giambattista Riccioli.