Observatio & demonstratio cometae aetherei, qui anno 1577 et 1578 constitutus in sphaera veneris, apparvit, cum admirandis eius passionibus, varietate scilicet motus, loco, orbe, distantia à terrae centro, &c. adhibitis demonstrationibus geometricis & calculo arithmetico, cuiusmodi de alio quoquam cometa nunquam visa est

(continues from previous page) a third referring to a part of the instrument used for measurement, which I will indicate elsewhere with God's help. I repeated these observations with careful diligence on the 22nd, 24th, 25th, 27th, and 28th of October, for the sky was clear around the evening twilight. On these days, I was able to see all the stars of Sagittarius very clearly, and indeed, the whole sky was visible to me. But if I want to confess the truth, no Comet was presented to me, either in Sagittarius or in any other part of the sky, which could have been seen much better in this region due to the lower altitude of the pole, since all the meridian stars are raised four whole degrees higher. Therefore, it is certain that if any Comet appeared there or elsewhere, it was far different from the one that showed itself to the whole world in the month of November, and it remained only in those regions. Yet, since it is said to have traveled around the Earth with the sky by daily motion motus diurnus daily motion, it certainly could not have hidden its splendor and light from these regions—and therefore from my observations, in which I noted the entire κατάσασιν state or arrangement of the sky not with sleepiness but with diligent inspection—no matter how little it might have been raised in altitude from the surface of the Earth. Furthermore, no parallax could have caused such a difference that it would not have arrived in our regions by daily motion. Therefore, let trust be placed in those authors. Rather, as will be demonstrated below, from the regularity of this Comet's motion, which it maintained from November 12th to January 8th Chap. 9., it can be gathered that if it had risen in October, it would certainly have preceded the rising Sun in the morning by a long interval. But all these things are contradicted by my evening and morning observations, by which I investigated the places of Saturn in the west, and Jupiter, Mars, and Venus in the east. Therefore, if there was such a one, it will not apply here.

That this Comet was not located in the sublunary sphere or the Elemental region, but in the upper world or the heavens themselves.

CHAPTER III.

With great industry, the minds of the ancient mathematicians, enlightened by God, investigated the various and manifold motions of all and singular stars, both fixed and wandering, and taught us to what certain laws of nature they are bound. Hence, we deservedly admire the subtlety of their divine genius, because neither the motions, nor the magnitudes, or