Usus Astronomicus Indicis Aspectuum veterum et praecip. novorum, compendiose sine Calculo simul omnium inveniendorum by BARTSCH, Jacob

Two folding engraved plates. Title within ornamental type border. 27 pp. Small 4to, attractive antique calf (small stain in outer blank margin), spine gilt, red morocco lettering piece on spine. Nuremberg: P. Fürsten, 1661. Second edition (1st ed.: 1624). Bartsch (1600-33), was Kepler's son-in-law and helped him compile his table of logarithms, assisted him on the Tabulae Rudolphinae, and, after Kepler's death, took over the printing of the Somnium but died before publication was completed. Bartsch studied astronomy at the University of Leipzig and medicine at the universities of Strasbourg and Padua. This is a work of practical astronomy and is most remarkable for its large (330 x 320 mm.) engraved plate depicting a horizontal planetarium (its workings are described in the text). In three of the outer corners there are engraved seven moving pointers intended to be cut up and mounted. In the introduction Bartsch praised the Strasbourg instrument maker Johann Friedrich Schmiedt for his knowledge and skills. He then describes the instrument based on aspects newly introduced by Kepler. In astrology, an aspect is an angle the planets make to each other in the horoscope, also to the ascendant, mid-heaven, descendant and other points of astrological interest. Aspects are measured by the angular distance in degrees and minutes of ecliptic longitude between two points, as viewed from Earth. According to astrological tradition, they indicate the timing of transitions and developmental changes in the lives of people and affairs relative to the earth. The instrument show seven concentric orbits of the planets in the Ptolemaic system and a hand or movable ruler. Fine copy. The 1624 is very rare. The Czech National Library has a copy with an engraved frontispiece. This seems to be the only recorded copy with a frontispiece. ❧ Lalande, p. 249. Zinner, Instrumente, p. 245.