REGIOMONTANUS, Joannes (1436–1476). Tabulae Directionum et Profectionum. Edited by Johannes Angelus. Augsburg: Erhard Ratdolt, 1490. [Bound with]: ANGELUS, Johannes (1543-1512). Astrolabium planum in Tabulis ascendens. Augsburg: Erhard Ratdolt, 27 November [or 6 October] 1488.

Otto Schaefer copy of two first editions of scarce astronomical texts printed by Erhard Ratdolt, 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 practioner of modern observational astronomy and influence on Copernicus, who owned a copy of this book. It is a series of tables for calculating the positions of celestial bodies—and a major advance in accuracy over earlier attempts such as the Alfonsine Tables.

The second work is 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. The result is a tightening of the broad mythological imagery of the constellations into a symbolic system for interpreting human nature and life, earning it a place in Aby Warburg's 1932 Die Erneuerung der heidnischen antike. Its visual program was linked from the 16th-century with the frescoes in the Salone of the Palazzo della Ragione in Padua via the influence of Pietro d'Abano, although modern scholars have called this into question. 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. H 1100*; BMC II 382; BSB-Ink E-63; GW 1900; Bod-inc A-283; Klebs 375.1; Goff A711; ISTC ia00711000.

Chancery quarto (221 x 160mm). First work: 156 leaves (some gatherings unopened, Tabella sinus recti bound at beginning instead of end as usual); second work: 176 leaves. Full-page woodcut of Ratdolt's device hand-colored in red at end of first work, 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). Contemporary vellum wrappers, title in ink on front cover, remains of paper label on spine; custom chemise and slipcase. Provenance: Otto Schaefer.