Miguel A. Granada (Barcelona): Aristotle, Copernicus, Rheticus
and Kepler on centrality and the principle of movement ......... 175
Harald Gropp (Heidelberg): New planets in the solar system: Uranus, Ceres and so on ........................................................... 195
Jesse Kraai (Santa Fe, NM): The four Copernican circles and Rheticus' heliocentric providence ............................................ 209
Richard Kremer (Dartmouth, NH): Copernicus among the astrologers: Apreliminary study .............................................. 225
Andreas Kühne (Munich): The reception of Copernicus as reflected in biographies ............................................................ 253
Richard Lorch (Munich): Copernicus'trigonometry ............... 269
Karl Röttel (Ingolstadt): Apian - Scheiner - Cysat: Beiträge Ingolstädter Astronomen im 16. und 17. Jahrhundert .............. 275
Section III: The significance of astronomy for the general development of science ........................................................... 295
William H. Donahue (Santa Fe, NM): Astronomy in the service
of cosmology? Kepler' s arguments for a finite universe ......... 297
Robert A. Hatch (Gainesville, FL): Nature's profoundest secret: First inklings, second guesses, second thoughts ...................... 307
Andreas Verdun (Bern): Methods of modern exact sciences in
the astronomical works ofLeonhard Euler ................................. 333
Section IV: The instrumentation of early modern
astronomy ................................................................................ 353
Sven Dupré (Gent): Optica est ars bene videndi: From
Gemma's radius to Galileo's telescope .................................... 355
Fernand Hallyn (Gent): Gemma Frisius, Mathematical
Practitioner and Humanist ........................................................ 369
Uta Lindgren (Bayreuth): Astronomische Vorbilder für geodätische Instrumente im 16. Jahrhundert ............................ 385
Salvo de Meis (Milan): From Regiomontanus to Kepler:
Accuracy and applications of astronomical ephemerides .......... 399