Johann Baptist Hebenstreit's Idyll on the Temple of Urania, the Frontispiece Image of Kepler's Rudolphine Tables, Part 1: Context and Significance

Abstract

1. PreambleThere is an extensive secondary literature on Kepler's Rudolphine tables, including a substantial body of work on its frontispiece depiction of a temple of Urania, Muse of Astronomy (Figure 1).' By contrast, Hebenstreit's poetic description of the temple has received relatively little scholarly attention.2 In his classic history of astronomy Jean-Baptiste Delambre described it as being mediocre verses;3 and in his edition of the Rudolphine tables Franz Hammer remarked if Delambre is correct in his judgement, it should be bom in mind Hebenstreit was given little time to complete the poem.4 Why has this portion of so famous a work been so little studied? The answer, we strongly suspect, has to do not with its quality but with its difficulty. As with much poetry of the period his hexameters are replete with learned classical allusions and echoes of ancient Roman poets. Its sentence structure is sometimes convoluted. As for the interpretation of the image it offers, it is not only complex and often ambiguous, but full of oblique references to technical aspects of Kepler's astronomy.A full study of the significances of this demanding poem would be a major undertaking. Our primary purpose here is more modest: to provide a literal translation with sufficient contextualisation and annotation to render the piece accessible to modern readers conversant with the history of astronomy. Accordingly, we first look at the circumstances of production of the poem. We next run briefly through it, pausing over some passages cast light on its aims and strategies. Then, after a discussion of the genres of the image and poem, we offer some tentative remarks on the messages conveyed, both openly and cryptically, in this remarkable composition.2. The Context of the PoemThe Rudolphine tables were initiated by Tycho Brahe, shortly before his death in October 1601.5 The task of completing the Tables then passed to Kepler, Tycho's successor as Imperial Mathematician to Rudolph n. A host of factors conspired to delay their completion. To start with one of Tycho's heirs, his son-in-law Tengnagel, contested Kepler's free access to Tycho's observations; this was settled only in 1604. But the heirs continued to make difficulties for Kepler over the issue of authorship and profits, and in 1612 he wrote to them committing himself to acknowledgement of Tycho as first author and to submission of the manuscript to them for approval prior to printing.6 Other sources of delay included Kepler's projects for the establishment of his own Copemican world system. Then there were arrears in his salary and difficulties in obtaining funds for production of the Tables from successive emperors, is, Rudolph until 1611, then Matthias up to 1619, then Ferdinand. From 1617 to 1621 Kepler was distracted by the protracted trial of his mother for witchcraft. Moreover, in 1617 there occurred what he described as that happy calamity, his encounter with Napier's logarithms, which prompted him to develop his own form of logarithms for use in the Tables.1 From 1618 there was the chaos of the Thirty Years War. But for all that, by 1624 the work was effectively complete, and for the next three years Kepler battled on, first in Linz and then in Ulm, struggling to obtain imperial finance, a sufficient stock of good paper, and a competent imperially approved printer. Kepler's relations with the printer finally chosen, Jonas Saur, were stormy: in mid-production of the work Kepler accused him of dishonest and threatening attempts to extort money from him; and he seriously considered taking legal action against Saur and transferring the printing to Tubingen.8 Finally, in mid-September 1627 a few copies appeared, rushed out for the Frankfurt Book Fair.In the final phases of production Kepler ran into further difficulties with Tycho's heirs, difficulties are directly relevant to the frontispiece image and the poem. …