Caput sextum. De situ huius cometae, quo ad mundi diametrum, ex ipsius parallaxibus; et an is in Aetherea, an vero Elementari regione extiterit, demonstrative concludere. Paravimus in omnibus antecedentibus viam ad investigandum...
moreCaput sextum. De situ huius cometae, quo ad mundi diametrum, ex ipsius parallaxibus; et an is in Aetherea, an vero Elementari regione extiterit, demonstrative concludere. Paravimus in omnibus antecedentibus viam ad investigandum demonstrandumque id, quod tantopere, tot iam elapsis seculis, ab omnibus pene philosophis, in varias sententias disceptatum est, et a nullo hactenus penitus decisum. Utrum videlicet possible sit, cometas in Aetherea mundi regione, intra orbes coelestes generari, an vero iuxta Peripateticorum placita, omnes infra Lunam, in suprema Aeris regione necessario versentur. Est sane hoc negotium, ut praecipuum inter ea, quae de cometis dici inquirique merito debeant, et sine quo caetera omnia, quae in medium adferuntur, manca existunt, ita etiam omnium difficilimum, et non solum labore, sed etiam magna subtilitate industriaque indiget: adeo ut vulgares astrorum observatores, cum suis puerilibus et ludicris instrumentis, prorsus respuat. Res enim versatur hic circa minima, ex quibus maxima concluduntur, cum illi ut plurimum circa maxima etiam caecutiant et aberrent. Ut ob id non usque adeo mirum sit, tantam esse discrepantiam inter philosophos hac de re, et tam diversas etiam neotericorum ex observationibus erroneis petitas sententias; adeo ut quamplurimi, qui de hac materia aliquid in medium protulerunt, etiam inter eos, qui non vulgares haberi volunt, longissime (quod salvo uniuscuiusque honore dictum volo) a scopo petito aberrarint, ut suo loco singulis satis evidenter demonstrabimus. Neque sane ulterius admiror, tot praestantes astronomos etiam hallucinatos esse circa parallaxin huius cometae indagandam demonstrandamque, cum non pauci ex iis parallaxin sensibilem Stellae Novae attribuerint, adeo ut quidam non dubitarint, Elementarem eam extitisse, pronuntiare. Cum tamen facilime, etiam absque ullo pene instrumento, depraehendi poterat, illam circa verticem aeque ac iuxta horizontem, eandem exquisite a vicinis fixis obtinuisse distantiam, quod fieri nequaquam potuisset, si adeo vicina nobis fuisset, ut Terrae semidiameter sensibilem parallaxin, cui ipsa etiam Luna obnoxia est, induxisset; Verum stella illa revera omnem aspectus diversitatem excludebat, et non aliter quam affixa Sidera, se respectu Terrae revolvebat; ut in priori libro, ubi de hac ex professo egimus, infallibili ratione aliquoties demonstratum reliquimus. Facilitatem autem huius rei observandae pervestigandaeque, peperit tum situs huius stellae semper aspectabilis, eo quod circulum circa Polum magnum quidem, sed cuius pars nulla occideret, motu primi mobilis designaret, neque adeo declivis in minima altitudine fieret, ut vapores circa horizontem, per radium refractum, locum eius aliorsum visui insinuarent, perpetuoque in eodem loco fixa stetit; unde motus proprius nullam in indaganda parallaxi difficultatem causari poterat. At in hoc cometa, quo ad parallaxes enucleandas, maior longe inest laboris perplexitas, et subtiliori opus erit pervestigationis methodo, neque etiam adeo simplici, eo quod is nec in meridiano aspectabilis fuerit, nedum ut non occideret, et motum etiam proprium obtinuerit, eumque non semper aequalem, sed successive se remittentem. Nos tamen certis et diversis rationibus, omnibus his difficultatibus praevenientes, liquido demonstrabimus, hunc cometam minime in Elementari regioni extitisse, sed longe supra Lunae sphaeram in ipso Aethere cursum suum absolvisse; Contra quam Peripatetici, Stagiritae illius authoritati insistentes, hactenus subtilibus suis argumentationibus, nulli tamen experientiae vel demonstrationi certae innixis, nobis persuadere conati sunt. Idque nunc eo audentius contra eos, eorumque asseclas asserere licebit, quod in Nova illa, de qua modo diximus Stella, in ipso Aethere insolitas generationes nonnunquam existere, adeo manifeste apparuit, certoque demonstrabatur, ut qui de hoc amplius haesitare velit, deridendus potius, et tanquam sensu communi carens, a veritatis schola explodendus merito veniat, quam ut responsione dignus censeatur. Cum itaque ratio investigandi parallaxin in hoc cometa, non usque adeo simplex et facilis (ut diximus) existat, qualis in Stella illa Nova sese obtulit, et multae viae alias a mathematicis praestantibus repertae sint ad parallaxium demonstrationem perveniendi; primum quidem ab eximio illo artifice Johanne Regiomontano Franco, edito de hac materia peculiari libello, tum etiam a quibusdam recentioribus non vulgaribus mathematicis: tamen cum nulla earum mihi satisfacere videatur, ad huius cometae parallaxes enucleandas, eo quod maxima pars transitum per meridianum aspectabilem praesupponat, et omnes illae viae, cometae motum nullum alium quam primi mobilis admittant, quae duo in hoc neutiquam locum obtinebant, adde, quod ut plurimum illae rationes, temporis exquisitissimam notitiam requirant, qua in parte quam facile aberrari possit, norunt, qui in hoc pulvere diligentius versati sunt; et ob id illae inductiones ex minimis, quorum parva aberratio, quae vix caveri potest, in maximam crescit deviationem, mihi semper suspectae fuerunt. Idcirco, ut nos in praesenti negotio, omnes a certitudinis scopo abducentes labyrinthos evitemus, et difficultatibus sese ingerentibus oportune occurramus, superatisque errorum scopulis ad veritatis planiciem exoptatam, conscendamus, tribus potissimum modis demonstrabimus, quod cometa hic Elementaris nequaquam extiterit. Primum, et quasi generali ratione, ex ipso ductu et motu, quem toto durationis tempore observavit, circulique tramite et declinatione, quem suo curso designavit. Secundo, particularius idem pervestigabimus ostendemusque ex distantiis a quibusdam peculiaribus fixis sideribus, viae cometae vicinis, quas interlapsis aliquot horis observavimus, cum altior decliviorque ipsius supra horizontem positus conspiceretur. Tertio, ex collatione observationum in semotis Sphaerae inclinationibus, ab aliis mathematicis exquisite deprehensis, et cum nostris, habita ratione interjectae Telluris portionis, diligenter collatis, idem enucleare conabimur. Confidoque his tribus comprobationibus certo convinci posse, cometam hunc supra Lunam, in ipso Aethere locum obtinuisse; quibus tamen, quasi appendicis loco, subjungamus aliqua exempla Regiomontanicae ratiocinationis, quae ex duabus datis altitudinibus et azimuthis, cum intervallo temporis cognito, parallaxin indagare docuit; ne veterum inventa vel ignorasse, vel neglexisse videamur, et ut id, quod prius innuimus, eiusmodi inductiones non ita bene in praxi atque speculatione locum obtinere, manifestum reddatur. Translation pp. 89-92 Chapter 6. To conclude demonstratively on the position of this comet, with respect to the diameter of the World; and whether indeed the comet appeared in the Aether or in fact in the region of the Elements. We have provided in everything that has gone before a way for investigating and demonstrating the question which has, over so many ages, been so much split by almost all philosophers into different opinions, and so far has not been completely settled by anyone: namely, whether it would be possible for comets to be generated in the aethereal region of the World, among the celestial orbs, or whether, instead, according to the views of the Peripatetics, all things under the Moon necessarily dwell in the uppermost region of the Air. Indeed, this issue is chief among those that should deservedly be discussed and inquired into regarding the comet, for without it, all the rest that have been brought forth would remain imperfect, so also it is the most difficult of all, and requires not only labour but also great subtlety and industry, to the extent that the question utterly spurns the common observers of the stars with their puerile and playful tools. For here the matter turns on very small things from which very great ones are concluded, whereas those [common observers] are usually blinded and also go astray regarding very great things. So that because of this, it is not surprising that so far there is such a discrepancy among philosophers on this matter and so many different claims on the basis of erroneous observations of the moderns, such that very many of those who have published something on this matter, even among those who do not want to be regarded as common (because I want what I say to respect everyone's honour), have strayed far from [their] intended target, as in due course, we shall demonstrate sufficiently clearly in the proper place. Nor indeed am I amazed that so many excellent astronomers have also hallucinated in investigating and demonstrating the parallax of this comet, since not a few of them have attributed a detectable parallax to the New Star, to the extent that some people have not hesitated to declare that the star appeared in the [region of the] Elements. But it could be grasped easily, even without any instrument whatsoever, that [the New Star] near the vertex and likewise near the horizon had maintained exactly the same distance from the neighbouring fixed stars, which could never have happened if [the New Star] had been so close to us that the radius of the Earth would have brought about the detectable parallax to which even the Moon is subject; hence that star truly excluded every difference in aspect [i.e. parallax] and carried itself around the Earth, just as a fixed star [does]; as in the former book where I dealt with this explicitly, we have shown demonstrated several times with infallible reasoning. But the position of this always visible star permitted this matter to be easily observed and investigated thoroughly, because the star described with the motion of the Prime Mover a large circle around the pole, no part of which set, nor did its declination come to a sufficiently small altitude for the vapours near the horizon to make its position appear differently to the eye through a refracted ray. And as it (the star) stayed fixed in the same position constantly, no proper motion could present difficulty in detecting...