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KEPLER, Johannes (1571-1630). Tabulae Rudolphinae, quibus astronomicae scientiae, temporum longinquitate collapsae restauratio continentur . Ulm: Jonas Saur, 1627. 2 o (338 x 222 mm). 4 parts in one (text and tables in 3 parts), the tables separately paginated and with section titles to parts 1 and 2, text in italic and roman, double column, printed shoulder notes. Engraved allegorical frontispiece of the Temple of Urania with astronomers, by George Celer after Kepler. First quire [):( 4 , containing two dedicatory letters to Ferdinand II, from Brahe's heirs and from Kepler] in Caspar's second state; second quire [):( ):( 4 ] in Caspar's third state (printed here on a different, slightly shorter paper). A few woodcut text diagrams, including full page of diagrams on k3v, woodcut initials, large woodcut device on part 2 section title. This copy includes the 4-leaf "Sportula genethliacis missa" (q 4 ) issued in 1629; it does not include the Appendix by Jacob Bartsch, added soon after Kepler's death in 1627, or the world map, dated 1630 but issued after 1658, that was added to some copies. (Diagram captions on k3v cropped, small faint marginal dampstain to frontispiece, small inkstain and trace of removed inkstamp on title, quire q 4 ["Sportula" leaves] slightly wrinkled and foxed.) 17th-century English speckled calf (rebacked preserving original backstrip, lower outer joint split, spine and extremities rubbed). Provenance : Earls of Bute, Luton Library bookplate. FIRST EDITION. On his deathbed in 1601, Tycho Brahe urged Kepler to complete his long-projected astronomical tables, to be based on Tycho's mass of astronomical observations and named after their patron Rudolph II. As Brahe's successor in the post of imperial mathematician, Kepler's principal task was the preparation of these improved astronomical tables. He worked on them for years, with frequent interruptions. "In his own eyes Kepler was a speculative physicist and cosmologist; to his imperial employers he was a mathematician charged with completing Tycho's planetary tables. He spent most of his working years with this task hanging as a burden as well as a challenge; ultimately it provided the chief vehicle for the recognition of his astronomical accomplishments" (DSB). When the work was finally ready for the press in 1624, there were further delays, not least the arrival of the Counter-Reformation in Linz, where Kepler was living and had planned to have the work printed. The edition was finally printed in Ulm, under Kepler's close supervision, in an edition of 1000 copies. "In excusing the long delay in publication... [Kepler] mentioned in the preface [p. 6] not only the difficulties of obtaining his salary and of the wartime conditions but also 'the novelty of my discoveries and the unexpected transfer of the whole of astronomy from fictitious circles to natural causes, which were most profound to investigate, difficult to explain, and diffiult to calculate, since mine was the first attempt'" (DSB). The greatly improved accuracy of Kepler's tables over previous planetary tables was due not only to his adherence to the Copernican system and his discovery of the laws of planetary motion, but also to the "happy calamity", as he put it, of his initiation into logarithms, through the intermediary of a small book by Benjamin Ursinus (the Cursus mathematici practici , Cologne 1618) which reproduced Napier's tables of logarithms. Kepler created his own logarithmic tables (published in 1624), and used them for the complex calculations required to determine planetary orbits. The superiority of his tables "constituted a strong endorsement of the Copernican system, and insured the tables' dominance in the field of astronomy throughout he seventeenth century" (Norman). Caspar 79; Houzeau and Lancaster 12754; Zinner 5063; Norman 1208.