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

...they seem such to themselves) as they did in the descriptions of previous comets, to describe their motion and tail only according to the regions of the winds. But comets demand a much more exquisite method of their motion. It suffices to delineate in this way the forms of chasms, trajectories, and other meteors, the sudden transit of which is considered not in the mobility of the sky, but in the immobility of the horizon. But comets, since they are movable together with the sky, and for the most part proceed in regular motions, and are seen for many days, require the same observations as the stars, both fixed and wandering (for they themselves are also stars lasting for a time). But since such people see that examining the true locations of comets, describing their motions and circles absolutely, finding their true distances both from other stars and from the earth through exquisite demonstrations, and so computing and explaining their phenomena Astronomically first, so that more certain Astrological predictions can be derived from them, etc.—that these things, I say, are not so profitable as they are laborious; and a great part of them pursues not the labors by which the liberal sciences are served, but the profits by which wealth is increased, or even the popular breeze: therefore, having taken no consideration of which part of the sky, in what place, sign, and degree, or how much it has receded from the earth (these, as not profitable, I wanted to say not necessary, they deem to be neglected), they descend to a prognosis, and that a very bold, not to say reckless, one, and sometimes begin to profess it when the comet has barely shone, for they know that it is received with open arms by the inept curiosity of the crude vulgar. But what is the excellence that those who are such perform? I will say what I feel, and what was done not so long ago. They openly betray their shameful ignorance in...