EXAMEN Astronomiae Carolinae: T. S. OR, A SHORT Mathematicall Discourse: CONTAINING, Some Animadversions upon Mr. THOMAS STREETES Astronomicall Tables of the Coelestial Motions Wherein his Errours and Mistakes are clearly detected, and the Author hereof justly vindicated from his unjust Aspersions. (In an APPENDIX to the said ASTRONOMICAL Treatise.) By Vincent Wing, Mathemat.
LONDON, Printed by W. Leybourn, for G. Sawbridge, at the Bible upon Ludgate Hill, 1665.
HONORABILI VIRO HENRICO NOEL ARMIGERO (Honoratissimi Baptistae Noell & Hicks, Baronis de Elmington & Ridlington, Vicecomitis de Campden, FILIO SECUNDO)
HOC OPUSCULUM QUALECUNQ INFAVORIS SUI COMMEMORATIONEM HUMILLIME.
To the Impartial READER.
FInding the very Fundamentals of Astronomy, not only undermin'd and much batter'd, but my self lately abused in Print, by that grand Calumniator, Mr. Thomas Streete; I have here undertaken, in a few Pages (so far as my urgent occasions would permit) to inform the World of the injustice of his actions, giving you a brief view of some of the most notable mistakes, and imperfections, committed in his late pretended Restauration of Astronomy. Yet (I confess to all) there is no man living that more values and esteems the just Attemps and Endeavours of those that are the Authours of any commendable Invention, then my self; yea, though it be but mean and ordinary, but especially ought we so much the more to esteem it, when the same is of a higher and more Sublime Speculation. But had our Antagonist been true to the Art be professeth, and (by the best of his endeavours) but rectified the Planetary-motions, Eclipses, &c. and made them more consentaneous [Page]to the Heavens, then was before performed, there might have been some ground for his suppositions; but the contrary clearly appearing (as may be seen in the following pages) it shews the very ground and foundation of his Superstructure to be sandy and imperfect. Neither doth the fixation of the Aphelions and Nodes of the Planets, any whit avail him, as the judicious Reader may find, by comparing his Tables with remote Observations, which (in some measure) we shall hereafter exhibite in the following Tractate, wherein you may see the manifold absurdities that follow upon his Suppositions. But I hope the more Learned are already sensible of the truth, and I believe (also) they will conclude that it's impossible for any man (from the Observation of the ☉ and ♀ Anno 1639.) to determine the Suns greatest Horizantal-Parallax to be only one fourth part of a min. and no more, (which is but one twelfth part of that quantity the noble Tycho observed) for admit the Parallax of ♀ from ☉ was 6 min. (as all our late Astronomers grant); yet that's not enough (as I conceive) to determine a thing of that consequence, in regard no Tables extant do agree exactly with the Observations of her place, but differ from some of the Tychonick Observations about a quarter of a degree, as his own Tables witness, which doubtless ariseth through the Refraction of this Planet, alway near the Horizon when the Observations were made; And besides, in that remarkable transit of Venus sub sole, juxta Horizontem, her Refraction from the Sun [Page]might neer aequalize her Parallax so near the Finitor, which you shall find agreeable to the Observations and Testimony of Walter Maestlin, Hortensius, and others, as we shall shew hereafter. And this may further appear from Tycho's Observations of her place made near the Horizon, which cannot be brought to the touchstone of Truth, neither can the best Artists in the World make their Tables to represent her place so exactly, with Observations, as they may the places of the other Planets taken at a farther distance from the Horizon, when they were freed from Refractions, as is well known to all that are Artists; and therefore why Mr. Street, or any man else, should grudge for declaring our dissent from his new Suppositions; I am ignorant, especially when they see (as they may in the subsequent discourse) that Astronomy is made infinitely worse thereby, and that the Planetary motions cannot neer so exactly be found out and determin'd, as otherwaies they may upon our Hypothesis, which is the main thing aimed at in all our Theories and Calculations. But I refer these things to the consideration of the judicious, hoping shortly to satisfie them in a more ample measure; in the mean time I commend these few lines to your serious perusall, and rest
Ad Amicum suum ingeniosum Vincentium Wing.
EXAMEN Astronomiae Carolinae, T. S. OR, Short Animadversions upon Mr. Thomas Streets Astronomical-Tables of the Coelestiall Motions.
SECT. I. Wherein is proved (by the indubitable Observations of the best, and most learned Astronomers) that Mr. Tho. Streets Tables of the Suns true place are not consentaneous to the Heavens, but very considerably differ from the most accurate Observations of all Ages.
FIrst, for the better confirmation and clearing the truth of our Assertion, We shall remove some Obstructions (out of the way of Tyroes) about the Parallax and Refrastion of the Stars, and especially Venus, that [Page 2]thereby the uncertainty of our Authors Suppositions may be the more apparent; and afterwards we shall examine his Tables of the Suns place, and compare them with the most accurate Observations of all ages, whereby I shall clearly make it appear that (in stead of a further Restauration of the Planetary Motions) he hath fallen much short of that exactness which is required, and already (in a large measure) performed by others. And this I shall principally prove by the Observations of those two excellent Astronomers, that noble Dane Tycho Brahe, and our late worthy Country-man, Mr. Edward Wright, unto whom assents, not only the two famous Astronomers, Kepler and Longomontanus, who were contemporary, and his assistants; but since, the learned Bullialdus, Ricciolus, Eichstadius, Argol, Gassendus, Norwood, and all other the most curious Observators, both of this, and other Nations, except Thomas Streete alone, who perhaps will strenuously endeavour to shelter himself under his false supputation of Parallaxes, but that cannot defend him, as we shall afterwards shew; for the greatest quantity of the Suns Parallax when he is fully freed from Refractions, in his Altitude of 45 deg. above the Horizon is but 1′.38″. which is so inconsiderable a quantity, that neither Mr. Thomas Streete, nor any he can procure to assist him, are able (by the best Observations they can make) to [Page 3]determine it more exactly, though he rashly (without any sufficient proof by Observations) diminisheth it to one 12th part of that quantity, which the Noble Tycho most curiously hath experimented from manifold Observations made with his large and costly Instruments, which for excellency was such, as never any Age afforded. All which Tychonick Observations, of the Suns true place (being faithfully compared with Mr. Streets Tables, and my own, I shall hereunder insert. Ut ex tantâ observationum harmoniâ (inquit Longomontanus lib. 1. Theoric. cap. 2.) quae in Tychonicis apparet, cum interpolatâ at (que) hiante veterum dissonantiâ comparata, posteritas justam occasionem nanciscatur D. Tychonis singularem industriam hic & ubi (que) gratâ mente agnoscendi, &c. And then speaking of the Suns Altitude, he shews his great care therein. Quae autem Altitudines meridianae Solis nunc ex Tychone sequuntur, duobus & interdum etiam tribus maximis & absolutissimis Quadrantibus, et insuper maximo circulo aequatorio Declinationis Caelitus acceptae, at (que) inter se limitatae sunt, adeont (nisi aere aliquando fortassis densiore omnem sensibilem errorem excludant, &c. So that from hence we see the admirable care and industry of Tycho in making his Observations. And besides I think Mr. Streete will grant this, That never any Astronomer, before, or since his time, was ever so compleatly furnished with such rare, exquisite, and truly admired [Page 4]Instruments, as the said noble Lord of Knudstrop, T. B. who expended no less then 200 Atti (que) Talents of Silver towards the Restauration of Astronomy, and rectifying the true place of the Sun. But would our Antagonist but acknowledge that which the noble Tycho, the learned Kepler, Longomontanus, Gassendus, Bullialdus, and all our modern Astronomers have observed about the Refraction of the Stars, he would never seek for any helps from the ♂ ☽♀ to assist him, seeing it was so near the Western Horizon, and Venus in less altitude then the Sun; so that (if any truth may be had from those most excellent Observations that severall Astronomers have made) she must then of necessity be subject to a greater Refraction then the Sun, though Mr. Street would perswade the contrary in the 25 Page of his Appendix) and the rather in respect of the Crassitude of the aereall-Sphaere. But this our Authour never so much as considers, or at least, not according to the Rules of Art, as may be seen in the 76 Page of his Book, where (upon this account) he hath quite lost himself, and so is not able to perform what (peradventure) he might otherwise intend. But because he may still contend about his doings herein (though to as little purpose as to throw stones against the wind), I shall here (before I come to Demonstration) shew from many select Observations, that the Refraction [Page 5]of Venus from the Sun, might then (in all probability) be as great, or greater, then the Parallax of Venus from the Sun. But if our Authour will not understand the truth thereof, what better Character can we give him, then that of Horace to one in the like case?
Now albeit the Refraction of the Stars is (in some measure) demonstrated in the Opticks of Vitellion, Alhazen, and others; yet it was never discover'd to any purpose, untill the rising of that great Luminary, Tycho Brahe, so that without controversie those Observations of the Suns true place made by the ancient Astronomers, must needs come much short of truth (which may be a good Monitum to Mr. T. S.) all which at this day we find fully made good by the collation of manifold Observations; and therefore saith Kepler in Astron. Optic. pag. 143. Magno Astronomiae damno in investigatione motûs solis & Aequinoctiorum factum est, ut Refractiones à Veterlbus fuerint ueglectae, &c. Yet Pliny gives us a clear Testimony of the truth thereof, Lib. 11. Hist. Nat. Cap. 13. in these words, Quâ nam ratione; cum solis exortu umbra illa hebetatrix sub terra esse debeat, semel jam acciderit, ut in occasu Luna deficeret, utro (que) super terram conspicuo sidere. Hence we may see (by this ancient Observation) that both the Sun and Moon, [Page 6]when they was in opposite places, distant one from another, a perfect Semicircle; yet for their Refraction above the Horizon, they appeared of a far lesser distance.
The like experiment we have of latter years, set down by Maestin in Thesibus [...]e Ecclipsibus, published Anno 1596. whose words in Thes. 55. are these. Anno 1590. die 7. Julii nos hic Tubingae, solis centro supra Horizontem emergente, vidimus Lunam ab austro aliquot digitis jam deficientem, duobus penè gradibus elevatam: & contra Lunae centro sub occasum descendente, notavimus solis supra ortum duorum graduum altitudinem. Which in plain English infers thus much (Mr. Streete) that when the Centre of the Sun arose above the Horizon, he saw the Moon almost two degrees high, Eclipsed some Digits on her South side. And contrariwise, when the Centre of the Moon touched the Western Horizon; He noted the Suns Altitude above the East, two degrees, and yet the Moon did set before the middle of the Eclipse. Hence we may conclude, that the Refraction of each Luminary was near a degree and half.
Again, the Lantgrave of Hessen (as it's mentioned, fol. 22. Epist. Tychonis) did on a certain night most exactly observe Venus to stand still (as it were) upon the Horizon, for the space of a quarter of an hour, and then suddenly to vanish. Kepl. in Astro. Optic.
Bernard Walter in Libro Observationum, testifies the same of Venus, and the other Stars, affirming Astra saepè supra Horizontem apparere, cùmreverâ sint infra. The Stars oftentimes appear above the Horizon, when they are truly beneath it.
But let us hear further what the same Authour saith, Anno 1489. die 6. Martii circa occasum solis, dum videlicet in medio Caeliesset 25. ♊ sol per armillas in 25°. 15′ ♓. Venus per alium circulum, Eclipticâ solem dividente, in 27°. 15′ ♈. inventa est: Sed circulo latitudinis solem mediante, utisolet circa Horizontem, in alio loco, puta in 25°. 30′ ♈. reperta est. Again, Die 7. Martii, sol per aspectum armillarum 26°. 15′ ♓. Venus ex Ecliptica 28°. 15 ♈. Ex circulo latitudinis 27°. 38′ ♈. And the reason thereof you may have in these words, Item, ne diutius lecturos lateat quomodo processerim, quodlocus Veneris quasi in eodem instanti adeò difformitèr repertus sit; est not andum, quod circa horizontem astra apparent propter radios fractos super horizontem, cum secundum veritatem sint sub eo. Here our Authour (by these Observations) plainly shews, That the place of Venus taken in the Horizon, is sensibly differing from her place in the Heavens, as he carefully experimented (observe it Mr. Streete) so that he thence concludes, That the Stars (in respect of their fracted raies) do appear above the Horizon, when, according to their true places, they are under it. Now I hope there are [Page 8]none that will deny the truth hereof, but such as take pleasure in their own foolish fancy, who very aptly verifie that saying, Contra omnes sapere disipere est.
Let us here further see what the learned Maestlin hath observed about the Refraction of the Stars, and especially Venus. Si nostris per Radium Astronomicum factis Observationibus fides sit habenda, non rarò invenimus veneris supra Horizontem altioris distantiam à sole juxta Horizontem posito, esse notabiliter minorem, quam si eodem die ejusdem distantia à sole altiore, & è vaporibus magis libero caperetur. Ergò solis altitudo per vapores, etiam per aeris super ficiem altior justo apparuit. Unde & ipsum, & alias stellas similiter supra Horizontem apparere posse, cùm infra adhuc sint, pro impossibili non habemus, sed certò concludimus.
Moreover in the year 1596. the Hollanders navigating along the Northern Ocean into Nova Zembla, to seek a passage into the Oriental Seas, they tell us, That being under the Elevation of the Pole 76 deg. oppressed by a night three moneths long, in a frozen-Sea, they concluded (according to Astronomical Principles) having taken their farewel of the Sun, Nov. 3. he would not return again to their View before the 11th. of Febr. 1597. but yet it so hapned (through the crassitude of the aereal Sphaere) that upon the 24 of Jan. (17 dayes before the due time) they saw the supreme margine [Page 9]of the Sun begin to appear in the very point of the Meridian, so that his Refraction above the Horizon was above 3. degrees and a half. Kepl. Paral. in Vitell. p. 138.
The learned Hortensius (speaking of the uncertainty of Tychoe's Observations of the place of Venus, by reason of her Refraction, to which she is commonly subject) lets not to affirm, That the true distance of Venus from the Sun, or from the fixed Stars, can in no wise be determin'd exactly. Sed pro variâ Altitudine, nunc majorem nunc minorem diversitatem inducit, & maximè circa Aequinoctia & Solstitium Hybernum, &c. which is excellently proved by the Observations of T. B.
Also in the year of Christ 1632. in the Moneth of Febr. Capt. T. J. Wintering in an Island of America, found the apparent time of the Sun rising 20 min. sooner then the true ought to have been, as may be seen in the Description of his Voyage, Pag. 64. whence it follows, That the Suns Refraction was almost 3 degrees.
Lastly, Tycho Brahe so diligently observed the just quantity of Refractions in the place where he lived, viz. Huenna, that we may certainly conclude, That the Stars are continually refracted in and about the Horizon, and yet not in all places alike, (as Tycho experimented after he came into Bohemia) for (as I shewed in my Almanack 1663.) [Page 10]in montanus places the Refraction is small, and sometime almost nothing; in places near the Sea, it is, in a manner, equall at all times of the year; and sometime again the Refraction is great and prodigious, which accidentally may happen in those maritime parts, where the Ayr is gross and thick; for the thicker and fuller of Vapours the Ayr is about the Horizon, the more it refracts the Star. So that from hence we may conclude, That the just quantity of the Refraction of the Stars (which Astronomers continually observe) cannot at all times be determin'd with certainty, especially when they are in, or near unto the Horizon.
Now from these Observations of learned able Mathematitians, we may clearly see how prodigiously the Stars are oftentimes refracted; and especially Venus, when she is near the Horizon, as we shall afterward evince by indubitable Experiments, and Demonstration Geometricall, whereby the judicious may see how dubious and uncertain a thing it is, to determine the Suns Horizontal Parallax to be only one fourth part of a minute.
Yet I am not ignorant of Kelper's Opinion, Epit. Astron pag. 479. where he saith, That if the Parallax of the Sun be 3 min. the Parallax of Mars in his nearest proximity to the Earth must be greater. Atque Observavi ego (saith he) Parallaxin Martis nequaquam esse sensibilem. Whence he imagineth, [Page 11]That the Suns distance from the Earth is more then 1200 Semidiameters. Again pag. 886. he supposeth the Parallax of Saturn to be 8″, Jupiter 15″, the Sun one min. or 60″, the Parallax of Venus in her Conjunction with the Sun about 4 min. o. sec. and Mars in Opposition of the Sun 2 min. 30′. sec. which (saith he) is scarce observable for the explication and circumradiancy of his beams. But this is but one Doctors Opinion, however I shall conclude with Kepler, That the Suns distance is greater then 1200 Semidiameters, namely 1460. Whereas Ptolomy makes it but 1165. Copernicus 1142. Tycho 1150. but our Antagonist increaseth it to 13755. Semid. and so maketh the Globe of the Sun to be 258309 times greater then the whole Earth.
Whereas Ptolomy, Albategnius, and Alfraganus made it but 166 times greater, and Tycho only 139 times. But I perceive our Antagonist would be singular, and counted absolutum Astronomiae Restauratorem, but the contrary will appear, and that (absque summâ curâ, & diligentia adhibitâ) he hath most erroneously stated the dimensions of the Caelestial Sphaeres, not duely considering some Observations, and wilfully rejecting others; for, ut quoties is antecedentium Astronomorum Observationes placitis suis non congruere cernit, toties eas limitet, castiget, emendet, rejiciat, aut [Page 12]malè invertat. But why could not Tycho (who was so curious and diligent) discover these rare secrets after he had made so many singular experiments about the Parallax and Refraction of the Stars? Certainly had there been just cause, or any real Observations of his, that would have made for these new suppositions, he would have seen it before our Antatagonist, but no such thing being by him (or by any other) perceived, neither sufficiently proved by ♂ ☉ ♀ Anno 1639. we can esteem his invention to be only, Purum figmentum, ex falsis, incertis (que) observationibus natum.
But to make a just Experiment of Refractions, and of the inequality and different degrees thereof; Take an empty Bason, or other Vessel, and in the bottome thereof place a piece of Silver, so that it cannot remove, then recede so far from the same till you just lose the sight of the Silver, which done, let one poure in fair Water into the Bason; and though you exactly keep your place of standing, yet shall you see the Silver refracted, and appear all to your eye; and the further you fill the Bason with Water, the more refracted, and the higher above the brim of the Bason will the Silver appear. So that by this experiment you may see the reason of Refractions, and after what manner they may be augmented or diminished, according to the crassitude of the medium, or areal Sphaere.
Again, if you place two pieces of Silver in the same Bason, one above another, and then go so far from the same till you see the Centre of the one agree exactly with the Centre of the other, then (as before) fill the Bason with water, and you will plainly see the Centre of the lower piece of Silver much more refracted then the other; which absolutely overthrows that in-artificial Discourse of T.S. about Refractions, as we shall see afterwards.
If then this be granted, (as it must of necessity) it will follow, that the nearer any Star is to the Horizon, the more it will be refracted in respect of the crassitude of the Ayr, and multiplicity of the vapours upon, and near to, the Superficies of the Earth.
Having now presented you with the former undeniable Observations of most learned Astronomers, we shall next (for the information of Mr. Thomas Streete) propound the Demonstration following (agreeable to the former experiment of two pieces of Siver put into a Bason) whereby he may clearly see (if he be not wilfully blind) that the Refraction of ♀ (in her ♂ with ☉, anno 1639.) was greater then the Refraction of the Sun.
In this Diagram, let A denote the Centre of the Earth, A Y its Semidiameter, D M N the extream limit of the aereall Sphaere, X E part of the Orb of ♀, and T S P part of the Orb of the Sun.
Now suppose O (in the ♂ ☉ ♀ anno 1939.) be the [Page 14] Sun, ♀ her place in respect of the Earth; I say the lines B ♀, O ☉, pass right forward towards the eye in Y, till they come to σ α, the points refringent, where falling obliquely upon the Atmosphaere, they are both refracted upwards, as from ♀ ☉, or rather B
O to Z S, the Sun appearing in S, and Venus in Z; so that the Refractions of B and O are not alike, because the crassitude of the aereall Sphaere Υ σ in Venus, is greater then it is in the Sun represented by Υ α. Hence (seeing that the Refractions are greatest in the Horizon, or little or nothing towards D) common reason, as well as Demonstration, will tell us, That the Refraction of ♀ in this position will exceed the Refraction of the Sun.
But let us hear the sensless Discourse of our Antagonist about Refractions. ‘Let the Planet (saith he) be free from the Suns contact, and grant as [Page 15]great a Refraction as any man can desire; I say that the space between them can onely be diminished (in like manner as the Suns vertical Diameter in his rising or setting seemeth less then his Horizontal) but no Contact, &c.’
Admit (as before) that Υ be the eye of the Observator, D the place of the Sun when he is elevated 45 degrees, and free from Refractions, T the place of the Planet in the Horizon; I say the line of vision τ σ passeth directly towards the eye, till it fall oblique on the aereall Sphaere in σ, from whence it is refracted upward from σ to α, so that the centre of the Star appearing in B to the eye of the Observator, the visible distance of the Centre thereof from the Centre of the Sun must in this scituation be equal to B D, which is much less then their true distance T D: Hence I conclude, That if the Sun be in the Horizon at O, and Venus at the point λ, (16′ depressed) and so no Contact as in that respect; yet because the Centre of ♀ in λ is more refracted then the Centre of the Sun above the Horizon at O (as appears by the former Demonstration and experiments) there must necessarily be a Contact, contrary to Mr. Streets supposition.
Besides we read in Authours, (as you may see above) That ♀, more then any of the other Planets, hath been very prodigiously refracted in and about the Horizon, yet we stand not here in any need of [Page 16]such Refractions; all that's required, (in that remarkable ☌ ☉ ♀, 1639.) is not above 3′ or 4 min. which though small, yet it's sufficient to defend our assertion: however, though the just quantity thereof may be drawn into question, yet it appears (as I said) but meer rashness, ob rationes praealligatas, to determine the just quantity of the Suns Parallax from that Conjunction, as I formerly hinted in my Monitum ad Astronomos, much less to make their Refrastions equal. Therefore what can I say further, but with Horace.
One of the greatest Arguments Mr. Streete useth is from the Observations of Mr. Horrox, whose Writings I never saw; but he tells us, Page 12. A.C. That comparing his Observations with others, he hath sufficiently proved, that the greatest Parallax of ♂ in ☍ ☉ is scarce at all observable, and never amounting fully to a minute, by which, and his excellent Telescope Observations of ♀ in the ☉, with her apparent Diameter at that time, and other good Arguments, he determines the Suns Horizontall Parallax to be one fourth part of a minute, and no more.
First, I would gladly know how he can make it appear, that the Parallax of Mars in his Acronical-Phases, is never so great as one minute; but I believe [Page 17]we shall find him as short in this, as in the rest, when we consider that the greatest quantity thereof (according to our limitation) contains only 2 or 3 min. but I need not stand to prove the invalidity of his assertion in this particular, in regard it is of the same nature with the former, and cannot (as I conceive) be determin'd exactly for the Reasons above given about Refractions; and the rather in respect of its small quantity. Neither can our Antagonist be ignorant, that the best Tables in being are not so well restored, but that the place of ♀ observed, varies sometime from them a 5th. and 6th. part of a degree; nay, sometime a 4th. part, as may be experimented from his own Tables, and therefore if there was no other Arguments, yet this were sufficient to shew how uncertain, yea, and impossible a thing it is to determine a business of such weight and importance from the Conjunction of the Sun and Venus: for though the Parallax of ♀ from ☉ in Altitude be six min. yet (as is said) the Refraction of ♀ supra ☉ something diminishing it, there can be left no ground at all for his suppositions, as may in due time more fully appear by our future Endeavours.
Neither can the apparent Diameter of ♀ in ☉ observed in that eminent Conjunction, anno 1639. stand him in any stead at all, for according to his own words, Pag. 76. the Semidiameter of Venus [Page 18]was observed about 39.′ which better agrees with our limitation, then with his own; for if the Semidiameter of ♀ in her mean distance be 12″. according to AB, (which is proved by Telescope Observations) the apparent Semidiameter of ♀ in her ☌ ☉, must be about 45.″ as may thus appear.
In the ☌ ☉ ♀ anno 1639. the distance of the Earth from the Sun was (according to A B) 98370. and the distance of ♀ from ☉, 72048, hence the distance of ♀ from the Earth 26322. of which part, (making the apparent Semid. of ♀ in mediâ distantiâ, 12.″) we limit the true Semid. of ♀ 5. 82 equal to B C.
Then in the Rectangle, Triangle AC B from
the Legs A C 26322. B C 5. 82. we shall find the angle of her apparent Semidiameter B A C to be 45.″ which is but a very little greater then Mr. Horrox sets down, but we shall find this diminished too; for if we do but consider that if a dark body (as ♀ in ☉ was) be put between any bright body and the eye, it will seem somewhat less then indeed it is, or will appear to be in another Scituation, which you may very easily experiment by holding a stick crosswise between your Eye and a Candle, so as the flame may be seen both above and beneath the [Page 19]same stick, whereby that part of it comprehended by the flame, shall be much less then the other parts of it, that are freed from the Raies thereof, as if on both sides somewhat were scraped or shaven away, (as Capt. Geo. Wharton judiciously observes) which is an undeniable truth, and agreeable to the following Aphorisme delivered by the learned Mathematitian, Dr. John Wallis of Oxford, which is this, Corpus lucidum dum radiis suis corpus opacum lambit, ipsius marginem ita perstingere solitum est, ut si non nihil inde abraderet, & corpus opacum paulo minus apparere facit, quam revera est.
I could here produce a Cloud of Witnesses against our Authour in this particular, and shew him, that 'tis altogether impossible to determine the Suns Horizontal Parallax to be just 15.″ and no more; but I shall now for brevity sake forbear, and the rather, because I am fully assured that it cannot be decided by no former Observations, no not by the most exact that ever was made; and therefore I shall rest upon Tycho's Observations, as the most exact, and give you the agreement of Mr. Streets Tables and my own therewith.
| obit. Alexandri | ☉ Street s d ′ ″ | Dif. ′ ″ | ☉ Wing. s d ′ ″ | Dif. ′ ″ |
| Mesor. 30 ☉ c. ☉ | ♎ 0. 37. 52 | 37 + 52 | ♎ 0. 27. 34 | 27 + 34 |
| Interc. 1 Manè | ♎ 0. 24. 16 | 24 + 16 | ♎ 0. 13. 52 | 13 + 52 |
| Interc. 1 Merid. | ♎ 0. 24. 43 | 24 + 43 | ♎ 0. 14. 19 | 14 + 19 |
| Interc. 3 Med. no | ♎ 0. 14. 40 | 14 + 40 | ♎ 0. 4. 9 | 4 + 9 |
| Interc. 4 manè | ♎ 0. 15. 8 | 15 + 8 | ♎ 0. 4. 35 | 4 + 35 |
| Inter. 4 Vesperi | ♎ 0. 1. 50 | 1 + 30 | ♍ 29. 50. 55 | 9 + 5 |
| Mechir 27 manè | ♓ 29. 55. 5 | 4 − 55 | ♓ 29. 56. 43 | 3 + 17 |
| Mech. 29 med. no | ♓ 29. 51. 4 | 8 − 56 | ♓ 29. 49. 29 | 10 + 31 |
| Pham. 1 in ☉ c. ☉ | ♓ 29. 15. 3 | 8 − 57 | ♓ 29. 52. 40 | 7 + 20 |
| Mar. | Loc. ☉ obs. | ☉ Street | Dif. | ☉ Wing. | Dif. |
| [...]. 14 | ♈ 3. 17. 40 | ♈ 3. 13. 12 | 4 + 28 | ♈ 3. 18. 6 | 0 + 26 |
| [...]. 11 | ♈ 1. 3 35 | ♈ 1. 0. 15 | 5 + 20 | ♈ 1. 5. 13 | 0 − 22 |
| [...]. 11 | ♈ 0. 37. 0 | ♈ 0. 31. 31 | 5 + 29 | ♈ 0. 36. 27 | 0 − 33 |
| [...]. 12 | ♈ 1. 21. 30 | ♈ 1. 16. 28 | 5 + 2 | ♈ 1. 21. 23 | 0 − 7 |
| [...]. 11 | ♈ 0. 53. 5 | ♈ 0. 47. 42 | 5 + 23 | ♈ 0. 52. 37 | 0 − 28 |
| [...]. 11 | ♈ 0. 37. 10 | ♈ 0. 33. 19 | 3 + 51 | ♈ 0. 38. 15 | 1 + 5 |
| [...]. 10 | ♓ 29. 54. 43 | ♓ 29. 50. 8 | 4 + 35 | ♓ 29. 55. 5 | 0 + 22 |
| 7. 10 | ♓ 29. 56. 20 | ♓ 29. 51. 56 | 4 + 24 | ♓ 29. 56. 53 | 0 + 33 |
| [...]pt. — | |||||
| [...]. 13 | ♍ 29. 36. 0 | ♍ 29. 38. 49 | 2 + 49 | ♍ 29. 35. 20 | 0 − 40 |
| [...]. 12 | ♍ 29. 21. 57 | ♍ 29. 24. 32 | 2 + 53 | ♍ 29. 21. 2 | 0 − 55 |
| [...]. 13 | ♍ 29. 51. 45 | ♍ 29. 55. 55 | 4 + 10 | ♍ 29. 51. 24 | 0 − 21 |
| 8. 12 | ♍ 29. 23. 30 | ♍ 29. 26. 21 | 2 + 51 | ♍ 29. 23. 57 | 0 + 27 |
| 0. 12 | ♍ 28. 53. 30 | ♍ 28. 57. 47 | 4 + 17 | ♍ 28. 54. 18 | 0 + 48 |
| 2. 10 | ♍ 27. 26. 15 | ♍ 27. 30. 22 | 4 + 7 | ♍ 27. 26. 54 | 0 + 39 |
| 4. 13 | ♍ 29. 56. 30 | ♍ 29. 58. 31 | 2 + 1 | ♍ 29. 55. 1 | 1 − 29 |
| 6. 14 | ♎ 1. 24. 10 | ♎ 1. 27. 21 | 3 + 11 | ♎ 1. 24. 22 | 0 + 12 |
| Time at London | Loc. ☉ obs. S O ′ ″ | ☉ Street. S O ′ ″ | Dif. ′ ″ | ☉ Wing. S O ′ ″ | |
| 1594 july 25 | ♌ 11. 29. 52 | ♌ 11. 32. 6 | 2 + 4 | ♌ 11. 30 50 | 0 |
| 1594 octo. 18 | ♏ 4. 42. 42 | ♏ 4. 44. 45 | 2 + 3 | ♏ 4. 41. 32 | 1. |
| 1595 april 8 | ♈ 27. 54. 16 | ♈ 27. 51. 13 | 3 − 3 | ♈ 27. 54. 36 | 0. |
| 1595 sept. 11 | ♍ 27. 44. 27 | ♍ 27. 48. 9 | 3 + 42 | ♍ 27. 54. 7 | 0. |
| 1596 mar. 13 | ♈ 3. 10. 48 | ♈ 3. 6. 39 | 4 − 9 | ♈ 3. 11. 14 | 0. |
| 1596 apr. 24 | ♉ 14. 9. 40 | ♉ 14. 5. 31 | 4 − 9 | ♉ 14. 8. 0 | 1. |
| 1596 aug. 10 | ♌ 27. 24. 24 | ♌ 27. 24. 59 | 0 + 35 | ♌ 27. 23. 11 | 1. |
| 1597 mar. 11 | ♈ 0. 57. 48 | ♈ 0. 53. 21 | 4 − 27 | ♈ 0. 58. 21 | 0. |
| 1597 mar. 12 | ♈ 1. 57. 55 | ♈ 1. 52. 39 | 5 − 16 | ♈ 1. 57. 35 | 0. |
| 1597 mar. 13 | ♈ 2. 56. 58 | ♈ 2. 51. 56 | 5 − 2 | ♈ 2. 56. 50 | 0. |
| 1597 már. 14 | ♈ 3. 56. 0 | ♈ 3. 51. 12 | 4 − 48 | ♈ 3. 56. 3 | 0. |
| 1597 apr. 30 | ♉ 19. 39. 22 | ♉ 19. 38. 16 | 1 − 6 | ♉ 19. 40. 42 | 1. |
| 1597 may 2 | ♉ 21. 35. 48 | ♉ 21. 33. 46 | 2 − 2 | ♉ 21. 36. 2 | 0. |
| 1597 july 24 | ♌ 10. 48. 8 | ♌ 10. 50. 34 | 2 + 26 | ♌ 10. 49. 14 | 1. |
| 1597 aug. 9 | ♌ 26. 11. 36 | ♌ 26. 13. 20 | 1 + 44 | ♌ 26. 11. 21 | 0. |
| 1597 sept. 22 | ♎ 9. 3. 26 | ♎ 9. 8. 39 | 5 + 13 | ♎ 9. 5. 3 | 1. |
| 1597 sept. 30 | ♎ 16. 59. 57 | ♎ 17. 3. 56 | 3 + 39 | ♎ 17. 0. 12 | 0. |
| 1597 octo. 6 | ♎ 22. 38. 13 | ♎ 23. 1. 52 | 3 + 39 | ♎ 22. 58. 8 | 0. |
| 1597 octo. 12 | ♎ 28. 56. 34 | ♎ 29. 1. 2 | 4 + 28 | ♎ 28. 57. 24 | [...]. |
In this Synopsis is inserted the place of ☉, as it's set down by Mr. Wright, pag. 310. & seq. the former 7. whereof are supputated from Mr. Streets Tables, and the rest are taken according to his own [Page 22]Calculation, as I find it set down in his Almanack, 1663. But our Antagonist may (perhaps) say, that because we do not admit of so great a Parallax in ☉ as Mr. Wright did, therefore this place ought to be corrected, and made agreeable to the true Declination. To this I answer, That the difference is so exceeding small, the errour will be insensible. But how near his Tables agree with Observation, the Reader may here see.
SECT. II. An Examination of Mr. Streets Tables of Eclipses.
HAving now made it appear by the Testimony of most accurate Observations, that our Antagonist hath much fail'd in the true place of the Sun, of which, I hope, the judicious are fully satisfied: I shall next shew the Reader some of the gross Errours he hath committed in his Doctrine of Eclipses; and to that end, I shall exhibite all those curious Observations made by the noble and learned Tycho Brahe, which without controversie, are the most exact that any Age ever before afforded.
| Temp. ap. modii Eclipsis Ʋranib. | ☉ Street. s d ′ ″ | ☽ Orb: Str: s d ′ ″ | Dif. ′ ″ | Di. Wi. ′ ″ |
| d h ′ | ||||
| 1573 Decem. 8. 8. 3 | ♐ 26. 50. 3 | ♊ 26. 53. 59 | 3 + 31 | 1 + 55 |
| 1576 Octo. 7. 11. 25 | ♎ 24. 33. 52 | ♈ 44. 28. 9 | 7 − 0 | 0 + 33 |
| 1577 April 2. 8. 50 | ♈ 22. 40. 38 | ♎ 22. 42. 32 | 2 + 19 | 2 + 31 |
| 1577 Sept. 26. 13. 3. | ♎ 13. 27. 18 | ♈ 13. 20. 3 | 6 − 48 | 1 − 7 |
| 1578 Sept. 15. 13. 24 | ♎ 2. 21. 56 | ♈ 2. 23. 53 | 3 + 57 | 0 + 15 |
| 1580 Jan. 31. 10. 10 | ♒ 21. 24. 27 | ♌ 21. 17. 0 | 8 − 17 | 1 + 21 |
| 1581 Jan. 19. 10. 0 | ♒ 10. 1. 2 | ♌ 9. 59. 45 | 0 − 40 | 1 + 12 |
| 1581 July 15. 17. 0 | ♌ 2. 44. 52 | ♒ 2. 48. 41 | 4 − 54 | 0 + 17 |
| 1584 Nov. 7. 13. 9 | ♏ 25. 51: 18 | ♉ 25. 52. 37 | 1 + 47 | 3 − 7 |
| 1587 Sept. 6. 9. 30 | ♍ 23. 11. 36 | ♓ 23. 17. 4 | 4 + 7 | 1 + 9 |
| 1588 Mar. 2. 15: 2 | ♓ 22. 44. 8 | ♍ 22. 44. 46 | 1 20 | 0 + 30 |
| 1590 Dec. 30. 7. 0 | ♑ 19. 6. 19 | ♋ 19. 12. 46 | 5 + 6 | 2 + 15 |
| 1592 June 14. 10. 20 | ♋ 3. 14. 37 | ♑ 3. 4. 45 | 8 − 39 | 2 + 11 |
| 1592 Dec. 8. 7. 41 | ♐ 27. 12. 45 | ♊ 27. 15. 23 | 4 + 49 | 0 − 9 |
| 1594 Octo. 15. 19. 16 | ♏ 5. 31. 41 | ♉ 5. 27. 3 | 5 − 59 | 0 + 26 |
| 1595 April 13: 16. 30 | ♉ 3. 20. 48 | ♏ 3. 18. 35 | 1 − 56 | 3 29 |
| 1595 Octo. 7. 20. 29 | ♎ 24. 19. 48 | ♈ 24. 11. 59 | 7 − 27 | 1 − 38 |
| 1596 April 2. 9. 25 | ♈ 23. 5. 28 | ♎ 23. 11. 56 | 8 + 39 | 1 + 29 |
| 1598 Febr. 10. 18. 7 | ♓ 2. 27. 6 | ♍ 2. 20. 55 | 7 − 18 | 3 + 1 |
| 1598 Aug. 6. 7. 37 | ♌ 23, 22. 13 | ♒ 23. 26. 6 | 2 + 50 | 0 + 59 |
| 1599 Jan 30. 17. 56 | ♒ 21. 6. 45 | ♌ 21. 6. 51 | 0 + 40 | 2 + 24 |
Hae 21. Eclipses Lunares (saith Longomontanus, Lib. 2. Theoric) maximâ exparte in Huenâ, binis, ternis, & quaternis interdum accuratissimis organis Tychonis Brahe; tum quoad initia, tum exitus, tum phases reliquas notabiles, quantum quidem Caelum permiserat, eâ diligentiâ acquisitae sunt, & ad veram ☍ Luminarium reductae, quae nunquam ab antecessoribus praestita est.
Although the true place of the Sun cannot (for the reason above given) be determin'd so exactly, but that it may still be called into question by the future attempts of others, yet here (I hope) Mr. Street will have the modesty to acknowledge the Errours of his Tables in this particular, if not, I shall contend no further, for I believe nothing will satisfie. Yet upon his submission, I will (if he request it) shew him away, whereby he may yet correct, and make his Tables more consentaneous to the Heavens. But what should I trouble my self, when we see the Gentleman so self-conceited, and proud of his own doings, which gives occasion for some to think that he is not in a capacity to learn, unless it be to mock and jeere, which he is now Doctor at, but I shall leave him here, and wish his Errours had not been so evident and clear, yea, to his very best Friends.
Turpe est Doctori cum culpa redarguit ipsum.
SECT. III. Wherein Mr. Streets Tables of the Praecession of the Aequinoctial Points and Places of the fixed Stars, are briefly examin'd.
NExt in contradiction (as it were) of all the Observations that Astronomers have made of the places of the fixed Stars, for the space of 1900. years before Tycho; he hath most apparently fail'd of that due exactness that is, and ought to be had: for if we look backward from Tycho to the time of Hipparchus and Timocharis, we may not only in their times, but in all the intermediate ages to this present, perceive his Tables to swerve continually from truth. And now, to the end, we may see the verity of our Assertion made manifest and apparent to the Eye of every one; I shall here present my Reader with the following Synopsis.
| Varii Authores. | Anni Christ. | Locum Stellarum Observ. | Di. St. deg. m. | Di. W. deg: m. |
| Timocharis | A. 284 | Siica ♍. 21.59. ♍ | 1 + 9 | 0 − 16 |
| Hipparchus | C. 120 | Siica ♍. 23.59. ♍ | 1 + 21 | 0 + 3 |
| Menelaus | Post Christum. 99 | Siica ♍. 26.15. ♍ | 1 + 58 | 0 + 57 |
| Ptolomie | Post Christum. 139 | Siica ♍. 26.43. ♍ | 2 + 15 | 1 + 3 |
| Ptolomie | Post Christum. 139 | Cor ♌. 2.30. ♌ | 2 + 16 | 1 + 17 |
| Albategnius | Post Christum. 879 | Cor ♌. 14.5. ♌ | 0 + 33 | 0 + 4 |
| Azophus | Post Christum. 937 | Cor ♌. 15.12. ♌ | 0 + 13 | 0 − 14 |
| Ebennesophim | Post Christum. 1364 | Cor ♌. 20.40. ♌ | 0 + 26 | 0 + 17 |
| Walther | Post Christum. 1504 | Spica ♍. 16.40. ♎ | 0 + 17 | 0 + 14 |
| Verner | Post Christum. 1514 | Spica ♍. 16.53. ♎ | 0 + 12 | 0 + 9 |
| Tycho Brahe | Post Christum. 1601 | Spica ♍. 18.16. ♎ | 0 + 0 | 0 0 |
Here you may see the Errours and Defects of Mr. Streets Tables of the places of the fixed Stars unmasked, and laid open to the View of every Reader, insomuch that the judicious do not a little admire, that (after his whole eight years labour) he should so far miscarry in a business of this kind, as not to heed either the Observations themselves, or that excellent rectification of their places that our modern Astronomers from thence have made,About a year since there came to my hands a Letter, from an ingenious Mathematitian, wherein (among other things) were these words; ‘There was never any Astronomer, either of this, or other Nations, that ever so erroneously stated the places of the fixed Stars, as Mr. Street hath done, making their places much greater in Longitude, then Observations will warrant, &c.’ and yet verily I am so charitable, as to think his intentions were good, and that he had not the least thoughts to rob the divine Urania [Page 27]of her comely Furniture, but rather to deck her in better Feathers; however, he may yet do well (for his Credit-sake) to shew some Reasons for his doings, and tell his Readers for what cause it is, that he so much dissents both from the Heavens, and all other Astronomers, which if he please publickly to communicate, we shall be ready to gratifie him for his pains, according to the utmost of his demerit; in the mean time, let him but seriously peruse the Observations of that ever honoured Dane, Tycho Brahe, and diligently compare them with the ancient and modern Observations, and he shall find the progression of the fixed Stars (equal to the praecession of the Equinoctial) to be annually 51 Seconds, or thereabouts; which quantity the learned Kepler most wittily retains in his Rudolphine-Tables: neither doth those learned Astronomers, Lansberg, Argol, Ricciolus, Bullialdus, or any other late Writers, much dissent from the same quantity; and yet now at last Mr. Tho. Street (as it were in Opposition to all these worthy men, yea, the Observations themselves) makes their annuall Progression onely 48 Seconds.
But let me tell Mr. Street, that the Progression of the fixed Stars in Longitude is (before his endeavours) so accurately rectified by sundry learned and judicious Artists of sundry Nations, that it is but meer rashness in him (or his adherents) to dissent from that quantity of motion so well already established by Observations, insomuch that to introduce Novelties into Astronomie, when there is neither reason, nor sufficient Arguments convincing us of the necessity of the attempt, is (Magnum et manifestum insaniae genus) the greatest folly in the World, and ought not to be passed over in silence. Si proximus deliquit, commone eum errati.
SECT. IV. Wherein is shewed, that if the Aphelions and Nodes of the Planets are alway fixed, it's then altogether impossible for Astronomers to determine exactly the true places of the Planets in all Ages.
OUr Antagonist (contrary to the Observations of all Astronomers, both ancient and modern) hath fixed the Aphelions and Nodes of the Planets under the eighth Sphaere, and so ties them [Page 29]alway, to one certain and determinate point therein, which is so far from Reason and Observations, that manifold Errours and Incongrueties do arise thereby, as we shall afterward shew. In the mean time I must tell him, there is no reall or sufficient ground for his Suppositions, seeing daily experience evinceth the contrary, and tells us, (and all others that have eyes) that their motions have no such dependance upon the eighth Orbe, (which is immoveable, and infinitely removed above them) but are moved by an inward moving force, (which doubtless is the great and glorious body of the Sun, placed in the Centre of their Vortex, there being rest in the Superficies, or Sphaere of the fixed Stars, and motion in the intermediate parts of the Planetary Systeme) which appears more clearly in the Moon, whose Apogaeon and Nodes (in respect of the celerity of her motion about the Earth) are observed to alter their places daily, not being tyed to any extraneous point whatsoever. But what need I stand to give any further Reasons, in regard the most ancient Observations, and also those in this present Age clearly confute this erroneous Supposition, as all the learned that are conversant in Cael stiall Observations and Theories Astronomical, do well know and observe; howbeit, if I should not produce some Observations exactly made, and compare them with his Tables, he will (I believe) neither [Page 30]understand the truth, nor see his Errours and Mistakes, though already obvious and apparent enough to the more learned and judicious: therefore I shall here present the ingenious Tyro with such a scale of Observations, and compare them with his own Tables, as I think will absolutely convince him of his Errour in this his most great and weighty enterprize.
But because their motions are slow, it thence follows, That if their places be exactly rectified to any certain or determinate point of time, there can be no sensible alteration, or errour arising in their motions for that age; but let the interval of time be considerable, and it will appear, and be as conspicuous as the Sun at noon-day, that they are not fixed, as he alleadgeth, but have their proper motions (some more and some less) as Observation do manifest, to which all our late learned and most industrious Astronomers do unanimously consent and agree. And this may excellently be proved by Observations of Jupiter, whose Aphelionis observed by all Astronomers, to move far more slowly then any of the other Planets; but if (according to Mr. Streetes Supposition) we make it equal to the progression of the fixed Stars, we cannot then (by the best Calculations we can from [Page 31]thence deduce) come to obtain his place exactly, either in preceeding or succeeding Ages. But that I may avoid prolixity, I shall now exhibite such Observations (though not many in number) whose truth and certainty are so conspicuous to every one, that (without dispute) they cannot be question'd by him, or any other.
First, I shall produce an Observation of Saturn made by the ancient Assyrians or Egyptians in the year from Nabonassar 519. upon the 14 day of the Moneth Tybi, at six in the Evening, (which our Author mentions, pag. 104. A. C.) at which time ♄ was exactly in Conjunction with the following Star in the left Winge of the Virgin, but was more Southward then the Star, two Digits, or five min. in respect of Latitude: Ptol. Lib. 11. Cap. 7. Magni Operis.
According to Mr. Streetes Tables, the Star wasin 6 deg. 58′ 30″ ♍, which (if true) should also be the place of Saturn; but you shall find by his own Calculation, that the place of ♄ then was in 7 deg. 16′ 50″ ♍, differing from truth 18 min. 20 sec. in Longitude, whereas my Tables in A. B. agree to 4 sec. giving the place of ♄ in 8 deg. 57′ 1″ ♍, and the place of the Star in 8 deg. 56′ 5″ ♍, &c.
Secondly, In the 83 year from the death of Alexander, and 18 day of the Moneth Epiphi, in [Page 32]the morning, the Star of Jupiter was seen to cover or hide the South Ass [...]llus. This was anno ante Christum 241. Septemb. 4. at two hours 30′ manè, in respect of the Meridian of London. Ptol. Lib. 11. Cap. 3. Magni Operis Astronomici.
But our Antagonist (being willing to save his Credit, and Cheat the World with his doings) hath not produced this famous Observation, nor so much as mention'd it in any of his Writings (which doubtless was because he saw it impossible to make his Tabl's agree thereto); therefore to undeceive his Readers, I shall here give you the Calculation thereof from his own Tables.
| S 0 ′ ″ | Log. dist. ♃ à | ☉—5.72072 | |
| Anno Chri. 1 | 0. 13. 54. 30 | Log. dist. ☉ à | Terra—5.00039 |
| Sub. 300 | 3. 14. 52. 30 | 0 ′ ″ | — |
| Ante Ch. 300 | 8, 29. 2. 0 | tang. 79. 13. 11 | 10.72033 |
| Adde 40 | 4. 13. 59. 0 | 0 ′ ″ | |
| Adde 19 | 7. 6. 34. 47 | R. tang. 34. 13. 11 | 9.83257 |
| September | 20. 11. 29 | tang. 34. 30. 13 | 9.83719 |
| Dies 4 | 19. 59 | tang. 25. 3. 6 | 9.66976 |
| Hor. 14 | 2. 54 | Sum. 59. 33. 19 | Elongatio |
| Scrup. 13 | 3 | Differ. 9. 27. 7 | Parall. |
| Ano med. ♃ | 9. 10. 10. 10 | Pro Latitudine | |
| Long. Helioc. | 2. 25. 22. 10 | 0 ′ ″ | |
| Longit. ☉ | 5. 4. 22. 36 | Sin. 69. 0. 26 | 9.97015 |
| Commntatio | 2. 9 0. 26 | Sin. 59. 33. 19 | 9.93556 |
| Parall orb. ad | 9. 27. 7 | Tan. 0. 23. 53 | 7.84182 |
| Loeus ♃ Sid. | 3. 4. 49. 17 | 17.77738 | |
| Praeces. ad | 3. 3. 44 | Trn. 0. 22. 3 | 7.80723 |
| Long. Geocen. | 3. 7. 53. 1 | The Latitude of ♃ North. |
The place of the Star at the same time was in 8° 34′ 44″ 69, with North Latitude 4′ 0″, so that the difference of Longitude was 41 min. 43 seconds, and of Latitude 18 min. 3 seconds, whereby the distance of their Bodies should be 45 min. 28 seconds, which is an Errour so intollerable, that our Antagonist cannot but blust to behold it. But if he be not satisfied of the truth of the Observation, let him read Ptolomie at the place above quoted, where he shall find these words, Anno 45. Dionysiano, die 10. Virginionis, sed à monte Alexandri [Page 34]anno 83 mensis Epiphisecundum Aegyptios die 18 manè, visus est ♃ occultare Asellum Austrinum.
I confess, they might be distant 7 or 8 min. and yet in respect of the Vibration of their Beams, Jupiter might seem to cover the Star; but had the interval of their Bodies been as much in quantity as his Tables do admit of, then certainly the Observator would not have said, that the one Star cover'd the other exactly, as the words of Ptolomy infer. Besides, Mr. Street might have taken Notice how neer other Tables agree thereto, as Longomontanus, Bullialdus, and divers others; but he that will make the Aphelion of ♃ to be alway distant from the first Star of Aries, 5 fig. 9 deg. 15 min. or indeed any other limited quantity, shall never reconcile, nor make his Tables to agree with the most approved Observations of all Ages.
I could here enumerate many other Observations of the like kind, as that of Timocharis mention'd by Ptolomy, Lib. 10. Cap. 4. who, Anno ante Christum, 272. Octob. 12. hor. 3. manè, observed Venus (at Alexandrid) exactly to be contained upon the former Star of the 4. in the left Wing of the Virgin, whereas his Tables differ above half a degree from truth. But because our Antagonist may wrest the Observation to his purpose, I will give you the words of Ttolomy, according to the most ancient Latine Copy, fol. 111. Anno 13. [Page 35] Philadolphi interdies 17. & 18. Mesori, vidit Timocharides stellam Veneris jam comprehendisse secundum veritatem, super stellam in extremitate alae Virginis meridionalis. And Copernicus renders the words thus, Quòd Venus visa fuit occupasse stellam, Lib. 5. Cap. 23. So Lansbergius, Praecept. 15. & fol. 172. Observat Astron. And Logomontanus, Lib. 2. Theoric. Cap. 19. Veneris stella cernebatur exactè obscurasse oppositum Vindemiatrici in 3° 10′. ♍, ubi & Venerem haesisse observatio habet. Yet I know, Bullialdus Astron. Philolaic. fol. 350. Thinks it was not absolutely a central Conjunction. Cum certum sit explicationem radiorum Veneris prius subtraxisse stellam oculo, quam interpositus fuerit ille Planeta inter fixam & oculum observatoris. So that we may conclude, That if Venus did not exactly cover the Star; yet it was so near, that she seemed to be contained upon it: And therefore how our Antagonist can excuse his Errour, I cannot tell. But ‘ [...].’
Again, for a further confirmation of his Errours, take that ancient Observation which Ptol. Lib. 10. Cap. 9. sheweth, was made in the 13th year Secun-Dionysium, Capric. 25. ubi [...]. That is, The morning Star of Mars was seen oposite, or adjoyned to the Northorn forehead of the Scorpion.
This was in the year before Christ 272. Jan. 17. Hor. 14.24′. in the meridian of London: At which time, we thus compute the place of ♂, according to the Tables of Mr. Street.
| s ° ′ ″ | |||
| Anno Chri. 1. | 9. 2. 3. 36 | ||
| Sub. 300 | 6. 1. 6. 0 | ||
| Ante Ch. 300 | 3. 0. 57. 36 | Log. dist. ♂ à ☉ | 5.205245 |
| Ante Ch. 300 | 3. 0. 57. 36 | Log. dist. [...] à ☉ | 4.994459 |
| Anni ad 20 | 7. 18. 4. 24 | ° ′ ″ | |
| Anni ad 8 | 3. 1. 13. 46 | ° ′ ″ | |
| Dies 17 | 8. 54. 31 | tang. 58. 23. 18 | 10.210786 |
| Hor. 14 | 18. 20 | ° ′ ″ | |
| Serup. 24 | 31 | R. tang. 13. 23. 18 | 9.376611 |
| Ano. med. ♂ | 1. 29. 29. 8 | tang. 59. 55. 57 | 10.237380 |
| Long. Helioc. | 5. 22. 5. 11 | tang. 22. 20. 58 | 9.613991 |
| Longit. ☉ | 9. 21. 57. 5 | Dif. 37. 34. 59 | Paralax. |
| Commutatio | 3. 29. 31. 54 | ||
| Parall. ad. | 1. 7. 34. 59 | ||
| Long. Geocen. | 6. 29. 40. 10 |
The place of Borealissima frontis was in 1°. 26′. ♏, so that his Tables in this Observation fail'd one degree and 46 min. from truth, a monstrous mistake!
Infinite Observations of this kind might be produced, to shew the falsity of our Authours Tables; but I shall neither trouble my self, or my Readers any further at this time, (I having more weighty [Page 37]Affairs continually to imploy my self about) yet I shall advise him (as one that wisheth well to his Studies) to write hereafter something to the purpose, and more civilly (as becomes a Servant of the Divine Urania) to argue and dispute Controversies in Astronomy, inutramque partem; especially when the thing is dubious, and scarce determinable by the most judicious. For my own part, as I love not busie Disputants, so would I advise my Readers to beware of their Sophistical Arguments; for 'tis no ill advise.
SECT. V. Wherein the Cavil of Mr. Street (in his Appendix) against our Demonstration of the transit of ♀ Subsole, is removed.
BUt our Antagonist being mindfull of the publique good, would teach us how to calculate the Angle of the visible way of Mercury with the Ecliptic, when he passeth between the Earth and the Sun, which method is no other, then what we have formerly made use of, as we shall hereunder demonstrate, only in the performance thereof (because it could breed little Errour in the matter aimed at (which is the Arch intercepted between their [Page 38]Centres) we took their true distance for ease of Calculation, whereas, according to exactness, we more properly ought to have taken their visible distance at the Earth. But had our Demonstration been false, as our Antagonist seems to infer, which will in no wise be granted him; yet in a matter of that nature, where little or no Errour ariseth thereby, it had been more commendation to keep silence: But he forgat that councell.
Now that I may prove that the Geometrical Method he makes use of, is no other in effect, then what we deliver'd, we shall instance in that remarkable Mercurial Eclipse, Anno 1661. April 23. (which was by us foretold, Part. 2. Ephem.) wherein the Latitude of ♉ at the time of the true Conjunction was 3′. 3″, but at 4 h.17′ 20″. after the true ♂ (when Mercury was exactly in her South Node) the Sun was in 13°. 39′ 48″ ♉, and Mercury in 13°. 23′ 0″. of
the same Sign, their distance 10′.48″. in respect of the Earth. Therefore in this Figure, let A. represent the Centre of the Sun, E Z H O his visible body, H D a part of the Ecliptic, P the Pole thereof, B the place of ☿ [Page 39]at the time of his Conjunction with the Sun, A B his latitude from the Ecliptic 3′ 3″, D the South Node of Mercury, A D the distance of the Sun from the Node 16′ 48″ which is equal to the Parallax of the Orb of ♀ in the Earth.
Then in the Triangle D A B, having D A 16′ 48″ and A B 3′ 3″, we shall find the Angle A D B 10 deg. 17 min. and consequently we shall from hence find the Arch B C greater by a quarter of a min. & A C the nearest appropinquation of their Centres 3′ 0″, whereas, taking their Heliocentric or true distance, (as we there did for ease of Calculation) it will be 3′ 2″. Or according to his Demonstration (which comes to the same thing) in the Triangle D P B, from the sides D P 90°. P B 89°. 56′ 57″ with the comprehended Angle B P D (=D A) 0°. 16′ 48″, we shall find the Angle P D B 79°. 43′, whose Complement is the Angle B D A 10°. 17′, and consequently A C will be found 3′ 0″, as before.
Thus Mr. Streete may see that our Demonstration is true, only taking the true distance for the visible, the Errour (in the matter aimed at) is only 2″, or a 30th. part of a minute: a thing so inconsiderable, that it had been more for his Credit to have spar'd his pains in that particular, yet Homo sum, humani nihilà me alienum puto.
To let pass the Errours of our Antagonist committed in some of his Demonstrations in A C. [Page 40](which are only obvious to the judicious) I could here enumerate many gross mistakes by him committed else-where, as that in his Ephemeris 1654, and the false Demonstration he there made about the Aequation of civil dayes; but I am not so envious and maligne, as to muster up the by-past slips and mistakes of any Author, especially such as are ingenious and deserving, though (really) Mr. Streete is altogether inexcusable, but I hope better things of him hereafter. In the mean time, let Mr. Streete take notice, that I value not his Bugbeare at the conclusion of his Monitum, where (thinking himself too weak to encounter me in a Combate of that nature) he threatens (as those use to do that set Scare-Crows) lest I hear from others as well as from himself. But 'tis but Mr. Streetes hopes, and vain desires doubtless: for I am of Opinion, That no man whatsoever (much less those that are Artists) will so much as attempt any thing of that nature, unless they had occasion. But I shall leave our Antaganist at this time, and refer him for the rest to my Astronomia Britannica, where he shall see (when published) such firm and real Demonstrations both in the Sphaeric and Theoric-parts of Astronomy (if he understand Latine) as may be useful for his Instruction, of which I shall give him a taste shortly, and so bid him farewel.