Might have missed one or two things but I've tried to type it out with long S's, typos and all.
And yes, clouds have been hiding the ſky from aſtronomers for some time.
Chich
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The Gentleman’s Magazine and Hiſtorical Chronicle Vol. XXIX. For the year M.DCC.LIX p 521-524
Mr Urban,
The return of a comet accurately foretold more than 50 years ago, is the only phaenonenon of its kind, and at the fame time one of the moſt intereſting to thoſe who are deſirous of forming the trueſt notions of the ſyſtem of the world. It was a happineſs reſerved for the aſtronomers of this age to be favoured with a more perfect and complete knowledge of theſe wandering bodies, which appear at certain times only, and after certain periods; of whoſe true motions, and even nature, the antients were ſo entirely ignorant, that the generality of them doubted even whether they were real bodies.
Dr. Halley formed a conſideration of the great influence which the planet Jupiter muſt neceſſarily have upon the comet during its laſt return in 1682, according to the theory of gravity, had ſaid that it was very probable that its next return would not be until aſter the period of 76 years or more, about the end of the year 1758, or the beginning of 1759. Some aſtronomers, without examining or weighingDr Halley's reaſons, and proceeding upon other principles,expected its return much ſooner. But M. Clairaut, upon a farther proſecution of Dr Halley;s principles and calculations, thought he could with ſtill greater preciſion foretel the time of its coming to its
The impatience of aſtronomers, and the deſire of verifying the ſucceſs of Dr Halley's prediction induced many to enquire in what part of the heavens the comet would firſt appear ; but, as they were ignorant of the preciſe time of its return, they could only know the place of its appearance, by making different ſuppoſitions concerning the time ofits paſſing the
Thoſe firſt obſervation were made with great difficulty. partly on account of the weakneſs of the comet's light, and partly becauſe it appeared near the horizon, and in the twilight. it was firſt ſeen in the conſtellation Pifces, or more particularly in the belly of the firſt or more westerly of the two fiſhes.
The comet was obſerved as often as the weather would permit, viz. on Jan. 22, 23, 25, 27, 28, 31, and on Feb. 1, 3, and 4. In regard to the appearance of the comet during this ſhort period, no great difference could be perceived on account of the different temperature of the air, which occaſioned the comet to appear more or leſs luminous. on the firſt of February, its apparant diameter was meaſured, and found to be two minutes and a quarter, and that of its nucleus to be 20 ſeconds.
The obſervations could not be continued in the evening any longer than the 4th of February, when the comet entered into the Sun's rays, and was no longer viſible. After it had ceaſed to appear, M. de l'Ifle endeavoured to determine, from the time of the
Unfortunately the heaven was covered with clouds almoſt during the whole month of March; but on the laſt day of the month ſome ſigns of a a clear ſky appear'd; and on the firſt of April the comet was diſcovered a little before four in the morning, about two degrees above the horizon. it was thought at that time to be larger and more brilliant than it was in February, and had a tail which was about half a degree in length, as it was eſtimated from the ſpace it occupied in the field of the teleſcope. The twilight, which grew ſtronger every day, ſoon deprived M. de l'Ifle of the pleasure of contemplating the comet, but not till he had compared it. tho' imperfectly, with ſome teleſcoptic stars, whoſe poſitions he was not able to determine. he continued to obſerve it as often as the weather would permit, vix. on the 3d, 6th, 7th, 8th, and 9th, of the fame month, at ſmall heights above the horizon, never exceeding eight degrees.
On the 14th it was obſerved in a perfectly ſerene and cloudleſs ſky, but the obſervation was rendered very imperfect by the brightneſs of the moon, which was then at the full ; the ſtrong light of which, with that of the twilight, hindered them from ſeeing the comet until it was four degrees high, At three quarters after three its nucleus could not be obſerved to be near the ſtars of the 3d or 4th magnitude, in the tail of Capricorn, marked γ and ẟ by Bayer. It was very near the more weſterly of the two stars, but its diſtances could not be determined exactly, the ſtrength of the twilight having ſoon cauſed it to diſappear.
On the 15th, however, the comet not withſtanding the brightneſs of the moon, was compared very exactly with the ſtar ẟ, from whence it was computed that the comet was in the 20th degree of Aquarius, with a South latitude ſomewhat exceeding three degrees.
On the 17th the comet began to appear before four o’clock, being them little more than two degrees high. It was fainter and more dim than on the day before, perhaps on account of the moon-light, and the twilight, and could not be perceived without great difficulty.
On the 18th, tho’ the ſky was perfectly ſerene, the comet could not be perceived ; and the obſerver could only account for his diſappointment from the brightneſs of the moon, and the ſtrong morning twilight.
Such is the hiſtory of the obſervations which could be made on the comet, after its emerging out of the the ſun’s rays. Its great increaſing South latitude would not permit the aſtronomers of this part of the world to ſee it during the remainder of the month; but, as its courſe in the heavens was ſufficiently known, M. de l’Ifle could with great certainty foretell that towards the end of April it would again appear above our horizon, after having run thro’, with a prodigious velocity, many of the ſouthern conſtellation, and having approached withing 16 degrees of the S. Pole.
Accordingly, by letters from the Weft Indies and North America, it appears, that the comet was ſeen there ſoon after the time of its paſſing the
After having left the conſtellation of Capricorn, in which it was laſt ſeen by the European aſtronomers, the comet paſſed thro’ the Indian, the Peacock, the Bird of Paradise, the Bee, the Croziers, and the Centaur ; from whence, towards the latter end of April, it drew neartotheconſtellation Hydra,and preſented itſelf once more to the European obſervers, paſſing on in a direction almoſt perpendicular to the horizon, and ſoon to be loſt in the Sextant under Leo.
From the imperfect accounts which had been received in England, that a comet had been obſerved by ſome of the French aſtronomers in the tail of Capricorn about the beginning of April, ſome of out moſt accurate obſervers here had reaſon to expect the appearance of this moſt remarkable comet above our horizon towards the end of that or the beginning of the following month. Accordingly on Monday the 30th of April, between 8 and 9 in the evening, the comet was ſeen by many curious persons. It was then in the conſtellation Hydra, marked ꭕ by Bayer, having about 172 deg. 30 min. of longitude, with about 31 deg. 30 min. In South latitude. The comet, unfortunately for aſtronomers, now paſſed on in a direction almoſt perpendicular to the the horizon, decreasing both in right aſcention and declination, but thro’ a tract of the heavens where there were few ſtars of the 1ft, 2d,3d or 4th magnitude, but ſuch as were ſo ſmall that their poſition could not then be determined. But as the ſeaſon is now advancing, when the places of thoſe ſtars may be aſcertained,we may ſoon hope to be favoured with the elements of the comet, for the time of its laſt return, with ſome degree of preciſion, more particularly if the French aſtronomers were enabled to determine its ſituation ſoon after it had paſſed the
During the whole of the month of May, the weather was in general favourable to the obſerver, and the comet was almoſt every night observed.
On the 4th, the ſky being perfectly ſerene, and the moon not riſing till ten,when the twilight alſo was weak, the comet was ſeen by the naked eye, and equalled in brightneſs ſtars of the 4th or 5th magnitude. The apparent diameter of its nucleus was found to be 27 minutes. On the 15th, the ſky being very ſerene as before, the comet when viewed by the naked eye ſeemed to have no tail ; for, even at the beginning of the month, ſo unfortunately was the comet ſituated, with reſpect to the earth and ſun, its tail was hardly of and conſiderable length, but appeared to the eye to be broad and ſomwhat fore-ſortened, and yet on this day we are told that de Iſle’s aſſiſtant, by means of a ſhort teleſcope, determined both the length and direction of the tail, and found it to be above three degrees long.
From the 16th the ſky continued to be very ſerene till the 22nd, during which time the comet was obſerved to diminiſh conſiderably in brightneſs, becauſe it was then at a very great diſtance ſrom the ſun. Its nucleus was conſiderably diminiſhed, and not well defined ; and its body, tho’ viſible enough in the teleſcope, could not be ſeen without great difficulty by eye.
From the 22d to the 28th the comet could not be diſtinguiſhed by the eye, On the 26th it was onſerved in the conſtellation of Hevelius’s Sextant, under a ſtar of the 5th magnitude called by Flamftead in regula ad pinnacidium. On the 28th it appeared nearly of the ſame size (tho’ rather with a ſtronger light) as on January the 21ft, when it was firſt diſcovered.
It was ſeen in France on May 30, and on June 2 and 3, but the light of the moon, which had entered into its ſecond quarter, ſo weakened the comet’s light, that the 3d was conſidered as the laſt day on which we ſould be permitted to ſee it. Tho’, as it would continue almoſt ſtationary,both in longitude and latitude, it might poſſibly be ſeen for ſome time longer, in the abſence of the moon, by the help of good glaſſes, gradually advancing to the North of its poſition on the 26th of May.
Such is the hiſtory, however ſhort and imperfect, of the obſervations of this comet, which have hitherto been made publick, or which have come to my hands. How far its elements differ from thoſe determined by Dr Halley, from Flamftead’s observations during the time of its appearance in 1682 (for there is perhaps a ſmall variation, both in the place of its nodes, and in the inclination of its orbit) muſt be determined by a more able hand, whenever a ſufficient number of good obſervations, taken in different parts of its orbit can be procured. However, from thoſe already made it moſt certainly and demonſtrably appears to be the ſame, the long expected comet, and therefore I cannot but congratulate my countrymen on an event ſo glorious to the Newtonian doctrine of gravity, and to the memory of that excellent philoſopher Dr Halley; and may it ever be remembered that the firſt inſtance of an event of this kind was foretold, and with accuracy too, by an Engliſhman.
As this comet was ſeen by the French aſtronomers ſo long ago as on January 21, I cannot help lamenting that not one here in England ſhould ſee it. I had amoſt ſaid, hear of it, till it had run thro’ the greateſt part of its viſible path ; and that the Engliſh aſtonomers ſhould be ſo ſingularily unlucky as not to be able to observe it, till at a time the moſt unfavourable for the purpofes of aftronomy. Whether de lIfle may not be charged with an unpardonable reſerve towards the reſt of his brethren, I will not preſume to determine ; but ſhall only add, that we of this iſland have great reaſon to lament that he did not communicate his intelligence to the greateſt aſtronomer in the world, whoſe unwearied diligence, and unparallel’d preciſion, will deliver his name to poſterity, to the honour of himſelf and of this nation.
Yours etc.
Astrophilus,