(KRUGER Piotr, Danzig), Petri Crügeri mathematici Dantiscani Doctrina astronomiae sphaericae, praeceptis methodicis et perspicuis per globum, tabulas, trigonometriam, tam veterem quam logarithmicam, explicata ac demonstrata:

Petri Crügeri mathematici Dantiscani Doctrina astronomiae sphaericae, praeceptis methodicis et perspicuis per globum, tabulas, trigonometriam, tam veterem quam logarithmicam, explicata ac demonstrata:

Cum tabulis ad eam pertinentibus. Cum privilegio regio ad annos XII. Dantisci (Danzig) 1635. apud Andream Hünefeldt M.DC.XXXV (1635). (17 x 11 cm), f. [8], pp. 175, [1]; 95, [1], 2 plates in copperplate (in place of 3), diagrams in woodcut in the text, 1 tab. typeset text, binding pperg. contemporary.
(Estr. T. 20). On the reverse of the title the privilege of Wladyslaw IV of 1633 forbidding reprinting under penalty of one thousand ducats. Dedication to the Senate of Gdańsk. Part II has the title: Tabulae quas vocant primi motus ad doctrinam sphaericam. Copperplate engraved by J. Hevelke (Hevelius) Part II has the title: Tabulae quas vocant primi motus ad doctrinam sphaericam. The work offered is a mathematical work on spherical astronomy, which Kruger considered part of theoretical astronomy. To determine the position of a star, he used an armillary sphere (ring sphere), an instrument that is a combination of several circles that can be adjusted so that their position corresponds to that of the circles of the celestial sphere. He made calculations by the method of prostapheresis and using logarithms. Peter Kruger (1580 Königsberg - 1639 Gdansk), mathematician, astronomer. Considered the most prominent astronomer of the Republic of the 1st half of the 17th century. Initially a proponent of geocentrism, he adopted the idea of Nicolaus Copernicus. He was the first to calculate the latitude of Gdansk (54° 22'), and made many maps of Gdansk and its environs. He also went down in history as the teacher of Danzig's most outstanding astronomer, Jan Hevelius. He gave him a solid foundation in mathematics and astronomy needed to continue his education. Traces of dampstaining and staining. Missing 3rd copperplate in copy. Good condition. The offered work of Peter Kruger, one of the most outstanding Polish astronomers after Copernicus and Hevelius, is one of the extremely rare astronomical and mathematical works of the 17th century. Estreicher locates only 2 pieces in BJ and Ossolineum.