It is striking how frequently he now compared the art of astronomical observation to learning and playing a musical instrument. To Aubert he wrote of the need to adjust each telescope individually and ‘to screw an instrument up to its utmost pitch. (As you are an Harmonist you will pardon the musical phrase.)’
Yet for some months Herschel had to continue to defend his telescopes against sceptics in the Royal Society. To the accusation that his discovery was by chance, they now added the implication that the huge powers of magnification he claimed were illusory. Particular scepticism was directed at his lens of 6,000 power, since it was calculated that a star so highly magnified would move through the viewing field of his telescope in ‘less than a second’, owing to the earth’s rotation. Therefore it would be quite impossible to observe. Herschel replied crisply that it took all of three seconds, and he could follow such a star very well.140 But to William Watson he complained that his critics evidently intended to send him ‘to Bedlam’, and wrote defensively on 7 January 1782: ‘I do not suppose there are many persons who could even find a star with my [magnifying] power of 6,450; much less keep it if they had found it. Seeing is in some respects an art, which must be learnt. To make a person see with such a power is nearly the same as if I were asked to make him play one of Handel’s fugues upon the organ. Many a night have I been practising to see, and it would be strange if one did not acquire a certain dexterity by such constant practice.’141
Watson quietly kept Banks informed of the controversy, while Banks gently temporised, suggesting that perhaps the magnifications were slightly miscalculated, but supporting Herschel against his detractors. He sent smiling presidential greetings: ‘My best Compliments to Mr Herschell, with best wishes for the Sake of Science that his nights may be as Sleepless as he can wish them himself.’142
Alexander Aubert now firmly took Herschel’s side. Thanking him for the catalogue of double stars, he remarked appreciatively on all the trouble Herschel had taken: ‘but trouble is nothing to you, and the least thing we can do in return is to … convince the world that though your discoveries are wonderful, they are not imaginary … Your great power of 6450 continues to astonish, your micrometer also … Go on, my dear Sir, with courage, mind not a few barking, jealous puppies; a little time will clear up the matter and if it lays in my power you shall not be sent to Bedlam alone, for I am much inclined to be one of the party.’143
Herschel’s next destination, as it turned out, was not Bedlam but Windsor. King George III, advised by the Astronomer Royal and the President of the Royal Society, had chosen to ignore these controversies. He summoned Herschel to court to congratulate him, but asked Banks and Maskelyne to make an independent trial of the now celebrated seven-foot telescope at the Greenwich Observatory. On 8 May Herschel left for London, his precious telescope and folding stand perilously packed into a mahogany travel-box (‘to be screwed together on the spot where wanted’), accompanied by a hastily assembled trunk of equipment including his large Flamsteed atlas (marked up by Caroline), his new catalogue of double stars (similarly written up by Caroline), ‘micrometers, tables, etc’, and rather makeshift court dress.144
At Greenwich, Maskelyne was stunned by the superior quality and light-gathering power of Herschel’s ‘home made’ mirrors. He immediately recognised that they were far more powerful than any of the official observatory telescopes, and probably than any other telescope in Europe. Maskelyne, reputed to be a jealous and illiberal man because of his supposed ill-treatment of the watchmaker John Harrison, behaved with great forthrightness and generosity to Herschel.
On 3 June 1782 Herschel wrote exuberantly to Caroline, casting aside his usual circumspect tone: ‘Dear Lina … The last two nights I have been star-gazing at Greenwich with Dr Maskelyne & Mr Aubert. We have compared our telescopes together and mine was found very superior to any at the Royal Observatory. Double stars they could not see with their instruments I had the pleasure to show them very plainly, and my [folding stand] mechanism so much approved of that Dr Maskelyne has already ordered a model to be taken from mine; and a stand to be made by it for his reflector. He is however now so much out of love with his instrument [a six-foot Newtonian] that he begins to doubt whether it deserves a new stand.’145
Banks (who had learned much about royal decorum since Tahiti) now knew that it was the perfect moment to introduce Herschel formally to the King at Windsor in May 1782. The meeting between the two Hanoverians (commoner and king, but both firmly speaking English) was a great success. Members of the King’s Hanoverian entourage had already heard of the Herschel brothers as talented musicians, and His Majesty was intrigued by the change in métier.146 King George, not yet mad, was renowned for his aphoristic remarks to his more talented subjects. To Edward Gibbon, for example, still deep in his six-volume history The Decline and Fall of the Roman Empire, he had observed archly: ‘Scribble, scribble, scribble, eh, Mr Gibbon?’ It was said that the King now murmured to Banks: ‘Herschel should not sacrifice his valuable time to crotchets and quavers.’147
Herschel wrote swiftly to Caroline, with a note of growing excitement that had never previously appeared in his letters. ‘Among Opticians and Astronomers nothing is now talked of but what they call my great discoveries. Alas! This shows how far they are behind, when such trifles as I have seen and done are called great. Let me but get at it again! I will make such telescopes & see such things — that is, I will endeavour to do so.’148 In a later note, again using her intimate diminutive name, he added: ‘You see Lina I tell you all these things, you know vanity is not my foible therefore I need not fear your Censure.’149 He would not have feared his sister’s censure a decade before.
Banks was determined to find his new astronomical protégé a salary, and if possible a suitable place. This required some diplomacy, as university professorships were for mathematicians, the post of Astronomer Royal was evidently taken, and the new post of Royal Astronomer at Kew Gardens had recently been promised to another — ‘a devil of a pity’. With Banks’s diplomatic nudging, the King agreed that Herschel should give up teaching music in Bath, and move to a house near Windsor, to concentrate entirely on astronomy. To achieve this, His Majesty would be pleased to create a new official post, appointing Herschel as the King’s Personal Astronomer at Windsor on a salary of £200 per annum. (This was not particularly generous, but then the Astronomer Royal received only £300.) At the age of forty-three, Herschel’s second career had burst into life.
After the very briefest consultation, Herschel, Caroline and their brother Alexander moved on 31 July 1782 to a large, sprawling house in the village of Datchet, positioned deep in the countryside between Slough and Windsor, just south of the river Thames. The house had large grass plots suitable for erecting telescopes, and several stables and outbuildings for the furnaces and the grinding and polishing equipment. An old laundry could be converted into an observation building. But the house itself had not been inhabited for several years, and was cold and damp. Caroline set about the huge task of cleaning and repairing.150
Almost immediately Herschel was commanded to bring his famous seven-foot telescope to Windsor, where it was reassembled on the terrace for everyone to view the planets. Herschel was a particular success with the three teenaged royal princesses, Charlotte, Augusta and Elizabeth. On one cloudy evening (it being an English summer) when viewing was impossible, he had the inspired idea of constructing pasteboard models of Jupiter and its four moons, and Saturn and its rings, and hanging them — illuminated by candles — from a distant garden wall on the Windsor estate. These were meticulously prepared beforehand. By ingeniously focusing down the seven-foot, he was able to show these models to the three young girls through the telescope, an early form of outdoor planetarium.151
Many other children of the new generation also grew up understanding the cosmos in a new way. Discovering the stars became a particular and special moment of self-discovery The poet Coleridge remembered being taken out at night into the field
s by his beloved father, the vicar and schoolmaster of Ottery St Mary in Devon, in the winter of 1781 to be shown the night sky. Coleridge was only eight, but he never forgot it. Perhaps the Reverend John Coleridge, a great follower of the monthly magazines (to which he sometimes contributed learned articles on Latin grammar), had recently read of Georgium Sidus. At all events, Coleridge treasured the memory of his father’s eager demonstration of the stars and planets overhead, and the possibility of other worlds: ‘I remember, that at eight years old I walked with him one evening from a farmer’s house, a mile from Ottery — & he told me the names of the stars — and how Jupiter was a thousand times larger than our world — and that the other twinkling stars were Suns that had worlds rolling round them — & when I came home, he showed me how they rolled round. I heard him with profound delight & admiration; but without the least mixture of Wonder or incredulity. For from my early reading of Faery Tales, & Genii etc etc — my mind had been habituated to the Vast.’152
Such a huge, starlit prospect, inhabited by giant planets and remote classical gods, might have puzzled or alarmed a normal eight-year-old. But the striking thing is that Coleridge, who wrote many letters about his childhood and always remembered it acutely, said he felt no surprise or disbelief at all — ‘not the least mixture of Wonder or incredulity’ –about this revelation of the enormous scale of the universe. He felt himself already tuned to the size and mystery of the new cosmos. His Romantic sensibility — even at the age of eight — already inhabited the infinite and the inexplicable. Cosmological imagery, and especially the symbolic movement of the stars and the moon, entered deeply into his early poetry, and in a sense it came to rule the world of the Ancient Mariner and his ship.
The moving Moon went up the sky,
And nowhere did abide;
Softly she was going up,
And a star or two beside.
Her beams bemocked the sultry main,
Like April hoar-frost spread,
But where the ship’s huge shadow lay,
The charmed water burnt always
A still and awful red.153
The prose gloss that Coleridge added to this passage almost twenty years later (1817) takes on a new resonance when compared with what we now know of Herschel’s long nights of lunar observation:
In his loneliness and fixedness he yearneth towards the journeying Moon, and the stars that still sojourn, yet still move onward; and every where the blue sky belongs to them, and is their appointed rest, and their native country and their own natural homes, which they enter unannounced, as Lords that are certainly expected and yet there is silent joy at their arrival.♣
The young John Keats remembered an organised game at his school in Enfield, in which all the boys whirled round the playground in a huge choreographed dance, trying to imitate the entire solar system, including all the known moons (to which Herschel had by then added considerably). Unlike Newton’s perfect brassy clockwork mechanism, this schoolboy universe-complete with straying comets — was a gloriously chaotic ‘human orrery’. Keats did not recall the exact details, but one may imagine seven senior boy-planets running round the central sun, while themselves being circled by smaller sprinting moons (perhaps girls), and the whole frequently disrupted by rebel comets and meteors flying across their orbits. Keats was later awarded Bonnycastle’s Introduction to Astronomy as a senior school prize in 1811. Reading of Herschel, he enshrined the discovery of Uranus five years later in his great sonnet of 1816, ‘On First Looking into Chapman’s Homer’.154
8
Once they had moved to Datchet, Herschel and his brother Alexander started an exclusive business in the manufacture of high-quality reflector telescopes. The first five of them, all seven-foot reflectors, were ordered by King George as royal gifts, and although never fully paid for by the Crown office (they were priced at a hundred guineas each), they had the invaluable effect of making Herschel the royal telescope-maker, ‘By Appointment’. All telescopes, whatever their size, were individually constructed to order, took three or four weeks to make, and had an individual price, usually quoted in guineas. Herschel would supply them either in kit form or fully assembled in beautiful mahogany cases, with spare mirrors and a selection of eyepieces. Although every one was handcrafted, his immense energy achieved something like mass-production. Over the next decade he made 200 mirrors for the popular seven-foot telescope, 150 for the ten-foot, and eighty for the big twenty-five-foot, although not all of these were sold.155
Prices rose steadily. The renowned seven-foot telescope was usually sold in kit form for thirty guineas, but Herschel gradually raised even the kit price to a hundred guineas, the figure he quoted to the German astronomer Johann Bode in Berlin.156 Eventually a twenty-foot in kit form sold for 600 guineas. The luxury ten-foot reflector, complete with polished mahogany case, patent adjustable stand, a selection of eyepieces and a spare mirror, cost a princely 1,500 guineas.157 Indeed the more expensive models were sold mostly to German princes, and models also went to Lucien Bonaparte (Napoleon’s brother) and the Emperor of Austria.158 Probably the most expensive commercial telescope that Herschel ever made was commissioned by the King of Spain for £3,500, and delivered to the Madrid Observatory in 1806.159 Scores of Herschel’s telescopes were eventually sent all over England and Europe, and he personally delivered one on behalf of King George to the state observatory at Göttingen in 1786.160
Gradually more and more visitors began to descend on the observatory at Datchet. Caroline started to keep a neat, double-columned visitors’ book, rather as if she were recording star observations, which in a sense she was. In spring 1784 the dying Dr Johnson sent the young Susannah Thrale (Mrs Thrale’s third daughter) on a visit, advising her to cultivate an acquaintance with Herschel: ‘He can show you in the night sky what no man before has ever seen, by some wonderful improvements he has made in the telescope. What he has to show is indeed a long way off, and perhaps concerns us little, but all truth is valuable and all knowledge pleasing in its first effects, and may subsequently be useful.’161
Caroline wrote vivid accounts of their routine of all-night star observations, or ‘sweeps’.162 Herschel’s technique of ‘sweeping’ did not — as the term seems to imply — involve moving the telescope laterally, which was always a tricky operation with the bigger reflectors. Instead it was kept on the meridian, and moved slowly up and down, while the constellations turned through the field of observation as the stars moved steadily across the night sky. As this motion is caused by the earth itself rotating on its polar axis, so the telescope is effectively ‘sweeping’ the heavens like some immensely long broom, or the finger of a searchlight. By this method Herschel could progressively cover the entire night sky in a series of small strips, each covering about two degrees of arc.163 The technique was far more accurate than any other stellar observation that had ever been undertaken before in the history of astronomy. But it was also immensely slow and painstaking. A complete sweep could take several years to complete.
During this time Herschel became so familiar with every part of the sky that he could identify stellar patterns, and any new objects, with amazing speed and precision. Perhaps his musical training helped him here, as much as his painfully self-taught mathematics. As he suggested himself, he could read the night sky like a skilled musician sight-reading a musical score. Or more subtly, the brain that was trained to recognise the highly complex counterpoints and harmonies of Bach or Handel could instinctively recognise analogous stellar patternings.
Herschel became fascinated by both the physics and the psychology of the observation process itself, and later wrote some of his most fascinating papers about it. From 1782 he began to record the many physical tricks his eyes could play, and also began to study the illusions of night observation. On 13 November, while trying to identify a new double star in Orion, he dictated a careful note to Caroline:
Following 10 Orionii. I saw very distinctly double at least a dozen times pass through the whole field
of view with both eyes, but was obliged to darken everything. I suspected my right eye to be tired, & know it to see objects darker. Therefore tried the left first, & saw it immediately pass thro’ the field double several times. Saw the same afterwards with the other eye … No star twinkled except Syrius, & those as low. The evening exceptionally fine for telescopes.164
The more he was challenged by professional astronomers, the more Herschel became conscious of his ‘art of seeing’, and how it needed explaining afresh. ‘The eye is one of the most extraordinary Organs,’ he repeatedly told his correspondents. Classical physiology was wrong. Visual images did not simply fall upon the optic nerve, in the same sense that they fell upon a speculum mirror. The eye constantly interpreted what it saw, especially when using the higher powers of magnification. The astronomer had to learn to see, and with practice (as with a musical instrument) he could grow more skilful: ‘I remember a time when I could not see with a power beyond 200, with the same instrument which now gives me 460 so distinct that in fine weather I can wish for nothing more so. When you want to practise seeing (for believe me Sir, — to use a musical phrase — you must not expect to see at sight or a livre ouvert) apply a power something higher than what you can see well with, and go on increasing it after you have used it for some time.’165
Caroline later assembled an index of all Herschel’s remarks on practical observation. Under ‘Trials of Different Eyes and Seeings’ she listed such topics as the distortion effect of ‘looking long at an object etc’, the need to progress from lower to higher powers of magnification, the fact that ‘different eyes judge differently of [the same] colours’, that ‘eyes tire’ without the observer noticing, and that ‘we see things always smaller at first, when difficult to be seen’.166