## Ephemerides novae motuum coelestium, ab anno vulgaris aerae MDCXVII [-MDCXVIII, MDCXIX, MDCXX]: Ex observationibus potissimum Tychonis Brahei, hypothesibus physicis, & tabulis Rudolphinis; ad meridianum Vranopyrgicum in freto Cimbrico, quem proxime circumstant Pragensis, Lincensis, Venetus, Romanus. Praemittitur I. Explicatio fundamentorum ephemeridis, praesertim ubi Motibus Lunae a libro Progymnasmatum Braheirsessum. Vbirespondetur ad crebr as interpellationes Davidis Fabricij Astr: Frisij, esjusq[ue] opiniones circa Vmbram Terrae & alias jucundas materias examinantur. II. Instructio super nova ephemeridis forma, & causae mutatae formae consuetae, ex sanioribus astrologiae fundamentis. Adjecta sunt primae Ephemeridi anni 1617. observationes meteorologicae ad dies singulos, & astronomicae nonnullae.

Linz: Johannes Plank, [1617-1619].

First edition, very rare and with an exceptional royal provenance, of Kepler’s *Ephemerides *for the years 1617-1620. These were the first tables of astronomical data calculated by Kepler on the basis of the new celestial mechanics he had published in *Astronomia nova* (1609), and also the first calculated using logarithms, preceding by a decade the *Tabulae Rudolphinae* (1627). The accuracy and reliability of Kepler’s ephemerides greatly surpassed those of other ephemerides of the time; as a result, the Copernican doctrine gained in esteem, and it was more and more accepted that it was not just a new and useful mathematical hypothesis, but a reflection of reality. In his important introductions to the tables, Kepler discusses sunspots (including his claim to have been the first of the century to observe them), his lunar theory, the application of logarithms (the ephemeris of 1620 is dedicated to their inventor, Napier), the *camera obscura *(which for Kepler was of great importance to astronomy), the final chapter in Kepler’s relations with the friend-turned-critic David Fabricius, and many other topics of the greatest interest in the history of science. “Already in 1609, at the time his *Astronomia nova* appeared, Kepler had formulated the plan of publishing ephemerides giving daily positions of the Sun, Moon, and planets for eighty years, beginning in 1582 with Tycho’s first systematic observations of the planets; the calculated positions would be derived from Tycho’s observations and from the new celestial physics that Kepler had developed in the course of his “war on Mars.” He hoped to enlist the assistance of Magini, the Bolognese astronomer, in carrying out the calculations, but this idea came to naught. The project on its way to realization had to be greatly curtailed in scope; its execution was delayed by the claims of other enterprises and by numerous calamities” (Wilson). A second volume of ephemerides, covering the years 1621-36, was published by Kepler at Zagan in 1630, shortly before his death on 15 November. ABPC/RBH list only one copy since the Honeyman sale (Swann, Apr 19, 2001, lot 184, $25,300). The Honeyman copy sold for £4,000 ($9,216) in 1980.

*Provenance*: Queen Sophia of Württemberg (17 June 1818 - 3 June 1877), wife of King William III of the Netherlands, full-page hand-written dedication in Latin, dated 1863, on front free endpaper from her to; Francis Napier, 10th Lord Napier and 1st Baron Ettrick (15 September 1819 - 19 December 1898), his bookplate on front paste-down. Queen Sophia corresponded with several European scholars, protected and stimulated the arts, and maintained warm ties with Emperor Napoleon III and Queen Victoria. Francis Napier, descendant of John Napier of Merchiston (1550-1617), the inventor of logarithms, was a Scottish polyglot, diplomat and colonial administrator; he served as British Minister to the Netherlands from 1859 to 1860, to Russia from 1861 to 1864, and as Viceroy of India from February to May 1872. A number of letters from Queen Sophia to Napier are preserved in the archives of the Malet family at Duke University. Kepler was born in the Duchy of Württemberg (now in southern Germany) in 1571, and his early studies were supported by the Duke.

In 1605 Kepler, then Imperial Mathematician to Emperor Rudolph II in Prague, completed the manuscript of *Astronomia nova*, which contained the first two of his three laws of planetary motion. “The great task which lay ahead of him, the great commission which he had to carry out, was to produce the astronomical tables planned by Tycho Brahe … Kepler could no longer depend on the theoretical hypotheses previously made in the calculation of the planet orbits. By the discovery of the planet laws he had created an entirely new foundation for this calculation. But since he had derived these laws solely from the observations of Mars, it was now necessary to demonstrate their validity for the other planets also and to calculate the elements of the orbits of these on the new basis … two more decades were to pass before the work was published [as *Tabulae Rudolphinae*, 1627].

“Associated with these astronomical researches is another work which likewise did not pass beyond the preparatory phase in the Prague period. The astronomical tables form the basis for calculating the ephemerides, that is the year-books which give the positions of the sun, moon and planets for each day of a year. Such ephemerides were very much in demand by astronomers who used them in their scientific researches, by seafarers who needed them for place determination, and last but not least also by calendar makers and astrologers to whom they were indispensable as supports for their prophecies. Kepler now planned to issue such an ephemerides and, moreover, for no less than eighty years. The year 1582 was to be the starting point because that was the year in which Brahe had begun his observations. From the year 1593 on, Kepler wanted to add his weather observations which dated from then, to get a sure basis for investigating the dependence of atmospheric conditions on the constellations in the sky. He wanted to complete this big work before publishing the [Rudolphine] tables. A double purpose guided him. In the first place, he wanted to be the one to reap the harvest which the treasure of Tycho’s observations and his own improved planet calculations promised; after the publication of the tables someone else could easily precede him in this. Secondly, the ephemerides, which he proposed to calculate in advance for the years to come, were to form a test of the accuracy of this new mode of reckoning and consequently for the trustworthiness of his theoretical bases for these calculations which were to be published in the tables” (Caspar, *Kepler*, pp. 178-9).

In 1611, the growing political-religious tension in Prague came to a head. Emperor Rudolph was forced to abdicate, and Kepler’s prospects under Rudolph’s successor (his brother Matthias) were dim. In the same year, his wife Barbara died from fever, and one of his children succumbed to smallpox. Following Rudolph’s death in 1612, Kepler moved to Austria to take up a position as teacher and district mathematician in Linz. “There were two plans which he now wanted to realize; both had already engrossed his attention in Prague. The one concerned the ephemeris … Kepler was occupied first in calculating the elements of the orbits of Venus and Mercury, a difficult task considering the extent of the Tychonic observational material. For whole months in 1614 - 1615 he sat over these calculations. The moon, with the numerous inequalities in its motion, gave even greater trouble. He worried over attempts to explain these inequalities physically, especially the variation, and to follow through the calculation of its physical concept accordingly. Hitherto it has hardly been noticed that here, too, he ran up against innovations in the framing of mathematical questions which deserve the interest of the mathematician and which were difficult to overcome with his tools. The year 1616 was primarily devoted to this painstaking work. Attacking the calculation of the ephemerides, the zealous scholar felt as though he had emerged from an abysmal sea. Waiting from March to May, 1617, at the court in Prague on the Emperor’s order, he utilized his free time to complete the ephemeris for 1617; that for 1618 he calculated in the following months at home in Linz. Johannes Plank began the printing immediately” (*ibid*., pp. 238-9). The second of Kepler’s plans was the preparation of his *Epitome astronomiae Copernicanae*.

In 1615, Ursula Reingold, a woman in a financial dispute with Kepler’s brother Christoph, claimed that Kepler’s mother Katharina had made her sick with an evil brew. The dispute escalated, and in 1617 Katharina was accused of witchcraft; in the autumn of that year Kepler was forced to travel to Württemberg to attend her trial (she was eventually imprisoned for fourteen months). After his return in the first weeks of the following year, he resumed work on the *Ephemerides *and *Epitome*, but this was again interrupted by calamity. “On February 9, his little daughter Katharina died. The father was oppressed by sorrow over this loss. “I set the *Tables *aside since they required peace, and turned my mind to the contemplation of the *Harmony* [i.e., *Harmonices mundi*]”” (*ibid*., p. 265).

“In the years 1617 - 1619, simultaneously with the *Epitome, *the first volume of the *Ephemerides *for the years 1617 - 1620 was completed. The publication of this volume had, as he says, given more printing work to him than to the printer himself. The supplementary printed ephemerides for 1617 contained his weather observations for each day of the year” (*ibid*., p. 300). Ephemerides were primarily numbers and the printer Plank did not have enough. Kepler therefore had to invest in his own set of numerical type. Only when these were available could Plank continue with the printing of the *Ephemerides*.

“Prefixed to the ephemerides for 1617 is the twelve-page “Responsio ad Interpellationes D. Davidis Fabricij Astronomi Frisij, Insertas Prognosticis Suis Annorum 1615, 1616, 1617”; it deals primarily with the nature of sunspots and the history of their discovery” (Wilson). “In *Phaenomenon singulare* (1609) [Kepler] reported on a presumed transit of Mercury that he had observed on 29 May 1607. Unfortunately, Kepler had caught between clouds only two glimpses of a “little daub” that appeared on the solar image projected through a crack in the roof. After Galileo’s discovery of sunspots, [Michael] Maestlin pointed out the error and Kepler ultimately printed a retraction in his *Ephemerides* for 1617, noting that unwittingly he had been the first of his century to observe a sunspot” (DSB).

“An additional topic [in the *Responsio*] is the optics of the *camera obscura*, which for Kepler had considerable astronomical importance. Fabricius had found from observations of occultations of stars by the Moon that the dark part of the Moon appeared to be of smaller radius than the illuminated part, and had concluded from this that the Moon was surrounded by an envelope of air which absorbed the sunlight. Kepler argued (correctly) that the phenomenon derived simply from the operation of the eye, which is a *camera obscura* and like all such has a finite aperture: each point of the illuminated object sends a ray of light through each point of the aperture, and as a consequence the object as “caught” on the retina appears larger than it really is” (Wilson).

“Logarithms play a major role in the construction of the ephemerides. Kepler first heard of Napier’s invention in 1617, obtained a full description of it in 1618, and by 1619 was computing his own logarithms, although he had not yet seen the Napierean logarithms or received an account of the way in which they were computed. The ephemeris of 1620 is dedicated to Napier, and all the ephemerides from that year onwards were calculated by means of logarithms” (*ibid*.). Kepler published his own logarithm tables, and an account of their construction, at Marburg in 1624/5 (*Chilias logarithmorum*).

“Of the accuracy of the tabular entries in Kepler’s ephemerides Bialas gives us a thorough account (pp. 534-47), using Tuckerman’s *Planetary, lunar, and solar positions* as a basis of comparison … he finds standard errors in Kepler’s ephemerides of about 6' for Saturn, Jupiter, and the Sun, of about 4' for Mars, and of about 10' for Venus and Mercury. These errors, he shows, are only occasionally due to computational mistakes; they derive principally from the exaggerated eccentricity that Kepler attributes to the Earth’s orbit, and from small errors in the orbital elements of the other planets. In a similar comparison with Tuckerman of the ephemerides for 1617 of Magini and [David] Origanus, both of them based on the Prutenic tables, Bialas finds the standard errors to be, for Saturn, 10'; for Jupiter, 13'; for Mars, 57'; for Venus, 37'; for Mercury, 3°26'; and for the Sun, 27' (Magini) or 5' (Origanus). The superiority of the Keplerian ephemerides is thus especially striking in the cases of Mars, Venus, and Mercury” (*ibid*.).

Extracts from Kepler’s *Ephemerides* were reprinted by Frisch in 1868 (*Joannis Kepleri astronomi opera Omnia*, vol. VII, pp. 479-666), but with the tables mostly omitted. The entire work was first reprinted in vol. XI of the *Gesammelte Werke*.

Caspar, *Bibliographia Kepleriana* 52; Houzeau & Lancaster 15040; Zinner 4594. Curtis Wilson, ‘Review of *Johannes Kepler Gesammelte Werke*, vol. XI, part I: *Ephemerides novae motuum coelestium.* Edited by Volker Bialas (Münich: C. H. Beck, 1983),’ *Journal for the History of Astronomy*, vol. 17 (1986), pp. 63-65.

4to (245 x 178 mm), pp. [xii], 1-39, [1, blank], [1], 40-45, [24, tables], [1, blank]; [7], [24, tables], [1, blank]; [7], [24, tables], [1, blank]; [7], [24, tables], [1, blank]. Printer’s device on titles to 1617 and 1618 ephemerides (those of the 1619 and 1620 ephemerides having drop-titles only), engraved initials, woodcut diagrams in text, stamp of Francis Napier to title partially erased. Nineteenth-century vellum, remains of ties, red lettering-piece on spine, ‘OBER RATH’ stamped in gilt on front cover. Fine and crisp throughout.

Item #4299

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Price:
$35,000.00
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