Consideratio & observatio cometae aetherei astronomica qui anno MDLXXX mensibus octobri, novembri et decembri in alto aethere apparvit

Furthermore, the other part is treated partly by others according to the precepts of Astrologers, insofar as it can be defined according to Physical causes, and partly it must be left to the singular divine providence. But the other part, which examines the magnitude of the prodigy astronomically, I have proposed to elucidate myself, namely the motion, place, and other properties, just as I had done for the previous Comet, insofar as it is bound by astronomical laws, so that the divine glory may shine forth better from it. These meditations of mine, Most Illustrious Prince and Lord, my Most Clement D., I decided to offer and dedicate to Your Highness humbly at the first opportunity once they were written, so that I might prove my studies and diligence to you, of which you kindly promise me all the best. But a change in my location and situation caused delays to this plan of mine, namely that I could not finish the complete calculation of this motion. For when, Most Illustrious Prince, my services were sought for the profession of Mathematics at the University of Heidelberg, Your Highness, partly to gratify the Most Illustrious Prince and Lord, D. Ludwig, Count Palatine of the Rhine, Arch-steward and Elector of the Holy Roman Empire, Duke of Bavaria, etc., my most clement lord, and also to congratulate the most ancient University of Heidelberg on the prosperous success of the reformation of the Holy Religion, and partly because, out of your ancestral and innate goodness and clemency, you have nothing more in your prayers than that you might faithfully promote those things which make for the tranquility of the Church and Republic and the happy growth of Schools, especially if they have been shaken for some time in turbulent states, to be restored and preserved, you kindly supported this most praiseworthy work, and dismissed me so that I might serve the Most Illustrious Prince Elector etc. and the most praiseworthy Academy. While I was coming here and managing my affairs to properly order the Sparta I had obtained, all the time passed in the meantime, so that for this calculation, except for a small amount, nothing remained. That, therefore, which was left, I spent on the examination of the motion of this Comet. Wherefore, Most Illustrious Prince, Most Clement Lord, I humbly beseech Your Highness.