Tabulae Directionum et Profectionum [& Tabella Sinus recti] by REGIOMONTANUS, Johannes

[Edited by Johannes Angelus]. White-on-black woodcut initials & a large woodcut printer's device in red at end. [156] unnumbered leaves (final two signatures bound at front in this copy, first few leaves a little frayed & lightly stained around margins), 40 lines, Gothic letter. 4to (220 x 164 mm.), cont. limp vellum (a little wrinkled). Augsburg: E. Ratdolt, 1490. [bound with]: ANGELUS (or ENGEL), Johannes. Astrolabium planum in Tabulis ascendens... Numerous woodcuts in the text, 7- & 12-line white-on-black woodcut initials. [176] unnumbered leaves (the final two are blank, four leaves misbound), 40 lines, Gothic letter. 4to (single small puncture hole in gutter in the second half of the book, occasionally touching a letter). Augsburg: E. Ratdolt, 27 November [or 6 October] 1488. First editions, and a most wonderful survival in a contemporary limp vellum binding (clearly intended to be temporary), of these two handsome and uncommon astronomical works; many outer and lower edges are uncut. From the library of Otto Schäfer, the great German collector. I. First edition of these notable tables, completed by Regiomontanus in Hungary in 1467 while serving as professor of mathematics at the newly-founded University of Pressburg (Bratislava) in Hungary. These tables were based upon both computation and the abundant observations made by Regiomontanus in Italy during the preceding years. "In 1467, with Bylica's assistance, Regiomontanus computed his Tables of Directions, which consisted of the longitudes of the celestial bodies in relation to the apparent daily rotation of the heavens. These Tables [were] computed for observers as far north of the equator as 60 degrees...in Tables of Directions he included a table of tangents (although he did not use this term) for angles up to 90 degrees...thereby providing the model for our modern tables."-D.S.B., XI, p. 350. This is an important contribution to the history of trigonometry. II. First edition of this richly illustrated astronomical book with over 400 fine woodcuts, including 80 miniatures, depicting the potential occupations or types of persons born under given auspices, large sets of the seven planets in chariots, and the twelve signs of the zodiac. Angelus (ca. 1453-1512), studied under Regiomontanus at the University of Vienna and took a medical degree in Italy. He returned to Augsburg where he established a medical practice. He remained active in the astronomical world by editing a number of texts by Arabic astronomers, earlier and contemporary astronomical writers (including Regiomontanus) as well as writing a treatise on calendar reform and many prognostications. In 1494 he joined the faculty at the University of Vienna where he spent the rest of his life improving Peurbach's planetary tables. Fine copies in what can be considered original state. Booklabel (loose) of Otto Schäfer. Preserved in a green morocco-backed slipcase. ❧ Regiomontanus: D.S.B., XI, pp. 348-52. Goff R-107. Klebs 834.1. Angelus: D.S.B., I, pp. 165-66. Goff A-711. Klebs 375.1. Stillwell, The Awakening Interest in Science during the First Century of Printing, 51-"an important astrological work containing tables of the sign and degree of the ascendent for each hour and minute.".