Tabulae directionum et profectionum. Tabella sinus recti. [Bound with:] ANGELUS, Johannes. Astrolabium planum in Tabulis ascendens.

Augsburg: Erhard Ratdolt, 2 Jan., 1490 & 27 Nov. (or 6 Oct.?) 1488. Two scarce astronomical texts in an attractive contemporary binding First editions of both works, each printed by Erhard Ratdolt, bound together in a contemporary vellum wrapper. Ratdolt was the greatest scientific printer of the incunable period, producing elegant and accurate texts of the most important astronomers and mathematicians of his time. The first text here is by Regiomontanus, an early practitioner of modern observational astronomy and an influence on Copernicus, who owned a copy of this book. It is a series of tables for calculating the positions of celestial bodies, a major advance in accuracy over earlier attempts such as the Alfonsine Tables. The Regiomontanus was edited by his former pupil Johannes Angelus (Johann Engel), who had studied under him in Vienna. He is also the author of the second work here, a profusely illustrated guide to the composition of horoscopes which functions as a visual dictionary of astrological symbolism. Drawing significantly from the earlier works of Julius Firmicus Maternus and Pietro d'Abano, the Astrolabium associates each ascending degree of the zodiac with an image representing a human quality. Both books are conspicuously rare in commerce, though well-held institutionally. This is the only copy of this edition of Regiomontanus to appear in auction records going back to 1975. In the same period only one other copy of Angelus's Astrolabium appears, lacking one quire. This copy is from the collection of German-Canadian doctor Otto Schaefer (1919-2009), a pioneer of Arctic medicine. Two works bound in 1 vol., chancery quarto (221 x 160 mm). Contemporary vellum wrappers attached to spine with two sets of six twisted vellum ties sewn through two leather patches, title in ink on front cover, remains of paper label on spine. Custom green morocco-backed bookform slipcase and chemise. Regiomontanus, 156 leaves (some gatherings unopened, Tabella sinus recti bound at beginning instead of end as usual); Angelus, 176 leaves. Full-page woodcut of Ratdolt's device hand-coloured in red at end of Regiomontanus, many woodcuts in text, woodcut initials. First few leaves a little dustsoiled, some light dampstains at ends, small puncture in gutter occasionally touching a letter, still very good, a most appealing volume. Regiomontanus: HC 13801* (incl H 15206*); BMC II 383; BSB-Ink R-82; Bod-inc R-041; Klebs 834.1; Goff R112; ISTC ir00112000; Stillwell Science 217. Angelus. H 1100*; BMC II 382; BSB-Ink E-63; GW 1900; Bod-inc A-283; Klebs 375.1; Goff A711; ISTC ia00711000.