astronomers-from-germany

"The employment of writing down the observations when my brother uses the twenty-foot reflector does not often allow me time to look at the heavens; but, as he is now on a visit to Germany, I have taken the opportunity to sweep in the neighborhood of the sun in search of comets; and last night, the 1st of August, about ten o'clock, I found an object very much resembling in color and brightness the 27 nebulæ of the Connoissance des Temps, with the difference, however, of being round. I suspected it to be a comet; but, a haziness coming on, it was not possible to satisfy myself as to its motion till this evening.""

"In my brother's absence from home, I was, of course, left solely to amuse myself with my own thoughts, which were anything but cheerful. I found I was to be trained for an assistant astronomer, and, by way of encouragement, a telescope adapted for 'sweeping,' consisting of a tube with two glasses, such as are commonly used in a 'finder,' was given me. I was 'to sweep for comets,' and I see by my journal that I began August 22, 1782, to write down and describe all remarkable appearances I saw in my 'sweeps,' which were horizontal. But it was not till the last two months of the same year that I felt the least encouragement to spend the starlight nights on a grass-plot covered with dew or hoar-frost, without a human being near enough to be within call; for I knew too little of the real heavens to be able to point out every object so as to find it again without losing too much time by consulting the atlas. But all these troubles were removed when I knew my brother to be at no great distance, making observations with his various instruments on double stars, planets, etc., and I could have his assistance immediately when I found a nebula, or cluster of stars, of which I intended to give a catalogue; .but, at the end of 1783, I had only marked fourteen, when my sweeping was interrupted by being employed to write down my brother's observations with the large twenty-foot. I had, however, the comfort to see that my brother was satisfied with my endeavors to assist him when he wanted another person, either to run to the clocks, write down a memorandum, fetch and carry instruments, or measure the ground with poles, etc., of which something of the kind every moment would occur."

"My dear nephew was only in his sixth year when I came to be detached from the family circle. But this did not hinder John and I from remaining the most affectionate friends, and many a half or whole holiday he was allowed to spend with me, was dedicated to making experiments in chemistry, where generally all boxes, tops of tea-canisters, pepper-boxes, teacups, &c., served for the necessary vessels, and the sand-tub furnished the matter to be analysed. I only had to take care to exclude water, which would have produced havoc on my carpet."

"With saddened heart but unflagging determination she continued to work for her brother, but saw his domestic happiness pass into other keeping. It is not to be supposed, however, that a nature so strong and a heart so affectionate should accept the new state of things without much and bitter suffering. To resign the supreme place by her brother's side, which she had filled for sixteen years with such hearty devotion, could not he otherwise than painful in any case; but how much more so in this, where equal devotion to the same pursuit must have made identity of interest and purpose as complete as it is rare! One who could both feel and express herself so strongly was not likely to fall into her new place without some outward expression of what it cost her—tradition confirms the assumption—and it is easy to understand how this long, significant silence is due to the light of later wisdom and calmer judgment which counseled the destruction of all record of what was likely to be painful to survivors.""

"It may easily be supposed that I must have been fully employed (besides minding the heavens) to prepare everything as well as I could against the time I was to give up the place of housekeeper on the 8th of May.""

""I wish you joy most sincerely on the discovery. I am more pleased than you can well conceive that you have made it, and I think I see your wonderfully clever and wonderfully amiable brother, upon the news of it, shed a tear of joy. You have immortalized your name, and you deserve such a reward for your assiduity in the business of astronomy, and for your love for so celebrated and deserving a brother."

"Wheras the people of the forenamed Ilandes, fled at the sight of our menne, the cause thereof was, that they suspected them to haue been Canibals, that cruel & fearse people which eate mans fleshe, which nacion our men had ouerpassed, leaninge them on the southsyde. But after they had knowledge of the contrary, they made greuous complaynt to our men, of the beastly and fearse maners of these Canibales, which were no lesse cruel agaynst them, them the Tyger or the Lyon agaynste tame beastes. Declaring furthermore, yt when soeuer they take any of them vnder the age of .xiiij. yeares, they vse to gelde them, & francke them vntyll they be very fat, as we are wont to doe with capons or hennes: and as for suche as drawe towarde .xx. yeare olde, to kyll them forthwith and pull out theyr guttes, and eate the same freshe and newe, wyth other extreme partes of the bodye, poudering the residue with salte, or keping it in a certayne pickle as we do iegottes or sansages."

"[A] description of the whole world with all that therein is."

"He is an astronomer of 33 years, held in high esteem by all specialists, a Bohemian Jew who... has worked exclusively in Germany at the largest institutes with very good success. This man has now lost, with brutal consequence, all possibilities, even the smallest ones, to earn his living, so now he has become without subsistance, and is literally forced to be a beggar. I have a handful of brilliant testimonies of him and his work. He has a wife and a child [Peter Beer]. ...he can be reached via Dr. Freundlich, Potsdam Astrophysical Observatory."

"Newton's own motto, "hypotheses non fingo" was, in a sense, disregarded by Newton himself: he rejected hypotheses only where they violated his own "regula philosophandi", that is to say, his principle of their strict parsimony. In terms of present-day methodology, we reject hypotheses as scientifically meaningless if they are incapable even of indirect test; and we reject them as superfluous or as implausible if they are too complex and artificial to conform with well established canons of inductive probability. But freedom of scientific theorizing must be preserved wherever the conditions of meaningfulness and of economy appear to be satisfied."

"In the year 1783 I finished a very good twenty-foot reflector with a large aperture, and mounted it upon the plan of my present telescope. After two years' observation with it, the great advantage of such apertures appeared so clearly to me that I recurred to my former intention of increasing them still further; and being now sufficiently provided with experience in the work which I wished to undertake, the President of the Royal Society, who is always ready to promote useful undertakings, had the goodness to lay my design before the king. His Majesty was graciously pleased to approve of it, and with his usual liberality to support it with his royal bounty."

"The number of compound nebulæ... being so considerable, it will follow, that if they owe their origin to the breaking up of some former extensive nebulosities of the same nature with those which have been shewn to exist at present, we might expect that the number of separate nebulæ should far exceed the former, and that moreover these scattered nebulas should be found not only in great abundance, but also in proximity or continuity with each other... Now this is exactly what by observation, we find to be the state of the heavens."

"The starlike appearance of the following six nebulæ is so considerable that the best description... was to compare them to stars with certain deficiencies."

"The number of stands I invented for these telescopes it would not be easy to assign. ...In 1781 I began to construct a thirty foot aërial reflector, and having made a stand for it, I cast the mirror thirty-six inches in diameter. This was cracked in cooling. I cast it a second time, and the furnace I had built in my house broke."

"A nebulous matter, diffused in such exuberance throughout the regions of space, must surely draw our attention to the purpose for which it probably may exist; and it must be the business of a critical inquirer to attend to all the appearances under which it will be exposed to his view..."

"We may conceive that, perhaps in progress of time these nebulæ which are already in such a state of compression, may be still farther condensed so as actually to become stars."

"In consequence of this arrangement I began to construct the forty-foot telescope about the latter end of 1785. The woodwork of the stand and machines for giving the required motions to the instrument were immediately put in hand. In the whole of the apparatus none but common workmen were employed, for I made drawings of every part of it, by which it was easy to execute the work, as I constantly inspected and directed every person's labor; though sometimes there were not less than forty different workmen employed at the same time. While the stand of the telescope was preparing, I also began the construction of the great mirror, of which I inspected the casting, grinding, and polishing, and the work was in this manner carried on with no other interruption than that occasioned by the removal of all the apparatus and materials from where I then lived, to my present situation at Slough."

"I was much hindered in my musical practice by my help being continually wanted in the execution of the various contrivances, and I had to amuse myself with making the tube of pasteboard for the glasses which were to arrive from London, for at that time no optician had settled at Bath. But when all was finished, no one besides my brother could get a glimpse of Jupiter or Saturn, for the great length of the tube would not allow it to be kept in a straight line. This difficulty, however, was soon removed by substituting tin tubes."

"In 1800 he had published his momentous discovery of infra-red rays; and in 1803 and 1804 his re-examination of double stars would reveal examples where the two components had orbited each other, visual proof that attractive forces...operated outside the solar system. ...between 1811 and 1818 he published four great synthetic papers on the construction of the heavens, in which he expounded the life-story of nebulae and clusters as they developed over time under the influence of gravity. ...Soon, development over time—in contrast to the unchanging clockwork universe of Newton and Leibniz—would become and remain part of astronomical thinking."

"Being self-taught, he had not known that astronomers were expected to focus on the solar system. Instead, he explored the construction of the universe, and it was on later generations that the questions he asked and the methods he devised to answer them were to have profound influence."

"William Herschel was the first man to give a reasonably correct picture of the shape of our star-system or galaxy; he was the best telescope-maker of his time, and possibly the greatest observer who ever lived."

"It soon appeared that my brother was not contented with knowing what former observers had seen, for he began to contrive a telescope eighteen or twenty feet long (I believe after Huyghens description)..."

"'We may... have surmised nebulae to be no other than clusters of stars disguised by their very great distance, but a longer experience and better acquaintance with the nature of nebulae, will not allow a general admission of such a principle, although undoubtedly a cluster of stars may assume a nebulous appearance when it is too remote for us to discern the stars of which it is composed."

"It will be necessary to explain the spirit of the method of arranging the observed astronomical objects under consideration in such a manner, that one shall assist us to understand the nature and construction of the other. This end I propose to obtain by assorting them into as many classes as will be required to produce the most gradual affinity... and it will be found that those contained in one article, are so closely allied to those in the next, that there is perhaps not so much difference between them... as there would be in an annual description of the human figure were it given from the birth of a child till he comes to be a man in his prime."

"A proportional condensation of the nebulous matter in the brighter places will sufficiently account for their different degree of shining."

"Instead of inquiring after the nature of the cause of the condensation of nebulous matter, it would indeed be sufficient for the present purpose to call it merely a condensing principle; but since we are already acquainted with the centripetal force of attraction which gives a globular figure to planets, keeps them from flying out of their orbits in tangents, and makes one star revolve around another, why should we not look up to the universal gravitation of matter as the cause of every condensation, accumulation, compression, and concentration of the nebulous matter?"

"We can hardly suppose a possibility of the production of a globular form without a consequent revolution of the nebulous matter, which in the end may settle in a regular rotation about some fixed axis."

"I compared also the present appearance of this nebula with the delineation which Huyghens has given of it in his Systema Saturnium... The changes that are thus proved to have already happened, prepare us for those that may be expected hereafter to take place, by the gradual condensation of the nebulous matter; for had we no where an instance of any alteration in the appearance of nebula, they might be looked upon as permanent celestial bodies, and the successive changes, to which by the action of an attracting principle they have been conceived to be subject, might be rejected as being unsupported by observation."

"I have made it a rule never to employ a larger telescope when a smaller will answer the purpose."

"When I resided at Bath I had long been acquainted with the theory of optics and mechanics, and wanted only that experience so necessary in the practical part of these sciences. This I acquired by degrees at that place where in my leisure hours, by way of amusement, I made several two-foot, five-foot, seven-foot, ten-foot and twenty-foot Newtonian telescopes, beside others, of the Gregorian form, of eight, twelve, and eighteen inches, and two, three, five, and ten feet focal length. In this way I made not less than two hundred seven-foot, one hundred and fifty ten-foot, and about eighty twenty-foot mirrors, not to mention the Gregorian telescopes.*"

"It's no exaggeration to say that modern astronomy was invented, more or less single-handedly, by William Herschel in the last decades of the eighteenth century."

"My brother wrote to inquire the price of a reflecting mirror for (I believe) a five or six foot telescope. The answer was, there were none of so large a size, but a person offered to make one at a price much above what my brother thought proper to give... About this time he bought of a Quaker resident at Bath, who had formerly made attempts at polishing mirrors, all his rubbish of patterns, tools, hones, polishers, unfinished mirrors, &c., but all for small Gregorians, and none above two or three inches diameter."

"This consideration must alter the form of our proposed inquiry; for the question being thus at least partly decided, since it is ascertained that we have rays of heat which give no light, it can only become a subject of inquiry whether some of these heat-making rays may not have a power of rendering objects visible, superadded to their now already established power of heating bodies. This being the case, it is evident that the onus probandi [burden of proof] ought to lie with those who are willing to establish such an hypothesis, for it does not appear that Nature is in the habit of using one and the same mechanism with any two of our senses. Witness the vibration of air that makes sound, the effluvia that occasion smells, the particles that produce taste, the resistance or repulsive powers that affect the touch—all these are evidently suited to their respective organs of sense."

"It is evident that we cannot mean to affirm that the stars of the fifth, sixth, and seventh magnitudes are really smaller than those of the first, second, or third, and that we must ascribe the cause of the difference in the apparent magnitudes of the stars to a difference in their relative distances from us. On account of the great number of stars in each class, we must also allow that the stars of each succeeding magnitude, beginning with the first, are, one with another, further from us than those of the magnitude immediately preceding."

"It is very probable that the great stratum called the Milky Way is that in which the sun is placed, though perhaps not in the very centre of its thickness. ...We gather this from the appearance of the Galaxy, which seems to encompass the whole heavens, as it certainly must do if the sun is within it."

"A standard of reference for the arrangement of the stars may be had by comparing their distribution to a certain properly modified equality of scattering. The equality which I propose does not require that the stars should be at equal distances from each other, nor is it necessary that all those of the same nominal magnitude should be equally distant from us."

"In this case, radiant heat will at least partly, if not chiefly, consist, if I may be permitted the expression, of invisible light; that is to say, of rays coming from the sun, that have such a momentum as to be unfit for vision. And admitting, as is highly probable, that the organs of sight are only adapted to receive impressions from particles of a certain momentum, it explains why the maximum of illumination should be in the middle of the refrangible rays; as those which have greater or less momenta are likely to become equally unfit for the impression of sight."

"To conclude, if we call light, those rays which illuminate objects, and radiant heat, those which heat bodies, it may be inquired whether light be essentially different from radiant heat? In answer to which I would suggest that we are not allowed, by the rules of philosophizing, to admit two different causes to explain certain effects, if they may be accounted for by one. ...If this be a true account of the solar heat, for the support of which I appeal to my experiments, it remains only for us to admit that such of the rays of the sun as have the refrangibility of those which are contained in the prismatic spectrum, by the construction of the organs of sight, are admitted under the appearance of light and colors, and that the rest, being stopped in the coats and humors of the eye, act on them, as they are known to do on all the other parts of our body, by occasioning a sensation of heat."

"Like Bradley, Herschel made an unexpected discovery in searching for parallax. He selected for observation stars close to each other in the sky, following the guidance of Galileo. Although Herschel failed to find parallax, he did find that in some cases the stars he observed appeared to be in relative motion around their common center of gravity. They were clearly "binary stars," bound by gravity to orbit one another. It is now realized that almost half of all stars can be found in binary systems."

"Hier ist wahrhaftig ein Loch im Himmel !"

"William as a natural historian of the heavens, a collector of astronomical specimens, was like a modern supertanker; once under way, it was almost impossible for him to stop. In 1802, when the campaign with the 20ft finally came to an end, the hundred or so nebulae of Messier had been augmented by no fewer than two-and-a-half thousand."

"William's catalogues [of nebulae] are... of the greatest significance in the story of the astronomy of the large-scale universe."

"I compared it to H Geminorum and the small star in the quartile between Auriga and Gemini, and finding it so much larger than either of them, suspected it to be a comet."

"William's chief reference... was A Complete System of Opticks, a two-volume work published in 1738 by Robert Smith, the same author whose [mathematics] book on harmonics [Harmonics, or The Philosophy of Musical Sounds] had captivated him more than a decade earlier. Smith explained the theory of optics but also gave step-by-step instructions on how to apply it to the construction and use of astronomical telescopes. ...word reached him that a Quaker gentleman who lived nearby was giving up his hobby, which just happened to be grinding telescope mirrors. William bought up his tools and some partially finished mirrors. The man gave him some lessons and then, armed with Smith's instructions, he went to work."

"In consequence of the harassing and fatiguing life he had led during the winter months, he used to retire to bed with a bason of milk or glass of water, and Smith's 'Harmonics and Optics,' Ferguson's 'Astronomy,' &c., and so went to sleep buried under his favourite authors; and his first thoughts on rising were how to obtain instruments for viewing those objects himself of which he had been reading."

""Planetarium" was written after a visit to a real planetarium, where I read an account of the work of Caroline Herschel, the astronomer, who worked with her brother William, but whose name remained obscure, as his did not."

"I must freely confess that by continuing my sweeps of the heavens my opinion of the arrangement of the stars and their magnitudes, and of some other particulars, has undergone a gradual change..."

"An equal scattering of the stars may be admitted in certain calculations; but when we examine the milky way, or the closely compressed clusters of stars... this supposed equality of scattering must be given up."

"An object may not only contain stars, but also nebulosity not composed of them."

"Nebulæ can be selected so that an insensible gradation shall take place from a coarse cluster like the Pleiades down to a milky nebulosity like that in Orion, every intermediate step being represented. This tends to confirm the hypothesis that all are composed of stars more or less remote."