Authors: Richard Holmes
Tags: #History, #Modern, #19th Century, #Biography & Autobiography, #Science & Technology, #Science, #Philosophy & Social Aspects, #Fiction
By the end of July Caroline had decided that the only way to remedy this situation was to insist on her own quite separate regime. She would be an astronomer, not a housekeeper. She would check over the calculations of William’s nebulae by day, and make her own sweeps up on the roof by night. She would go to bed late (often just before dawn light, around 4 a.m.) and get up late (but always in time to pay the workmen after breakfast). She even wrote William a little imaginary letter about this in her ‘Book of Work Done’. In this case it was to be work she would
not
do. ‘I find I cannot go fast enough with the registering of sweeps to be serviceable to the Catalogue of Nebulua. Therefore I will begin immediately to recalculate them, and hope to finish them before you return. Besides I think the consequences will be bad of registering the sweeps backwards.’
18
Thus liberated from the nightly duty of William’s sweeps, her ‘Book of Work Done’ began to fill with her own astronomical observations. Symbolically she recorded on 30 August winding up the ‘Sidereal Time Piece’, the big brass chronometer used to fix stellar positions.
Three summers previously William had built Caroline a special two-foot Newtonian reflector, mounted within an ingenious wooden box-frame. Because of its large aperture, its tube appeared much fatter, heavier and stubbier than normal reflectors of this type: a rotund, almost jovial presence, but not in the least awkward to handle. Suspended from a pivot at the top of the box-frame, the telescope could be precisely raised or lowered by a system of pulleys operated by a large brass winding handle at the bottom. These adjustments were easy to make, and extremely fine. The whole ‘contrivance’ was set on a solid portable wooden stand, constructed like a three-legged stool, and exactly carpentered to bring the Newtonian viewing lens precisely to the level of Caroline’s eye. It also allowed a workman (or Caroline herself) to carry the telescope and stand in two sections, and position it wherever required, downstairs in the garden or upstairs on the flat roof.
19
This beautiful instrument was designed specifically for its huge light-gathering power and its wide angle of vision. The mirror was 4.2 inches in diameter (the size more usually placed in the seven-foot reflectors), with a large observational field of over two degrees. The magnification was comparatively low at twenty-four times. As with modern binoculars, this combination of low power with a large viewing field allowed the observer to see faint stellar objects very brightly, while placing them within a comparatively wide context of surrounding stars. In effect, Herschel had constructed for Caroline
a hunter’s telescope.
It was a deliberate challenge. The instrument was not suitable for deep space, but it was perfectly designed to spot any strange or unknown object moving through the familiar field of ‘fixed stars’. It was designed to find
wanderers
and
messengers
coming into the solar system. In other words, to catch new planets or new comets. It eventually became famous as ‘Miss Herschel’s small sweeper’, and would be joined within two years by ‘Miss Herschel’s large sweeper’.
20
On 1 August 1786, only two nights after starting her new sweeps, Caroline thought she had spotted an unknown stellar object moving through Ursa Major (the Great Bear constellation). It appeared to be descending, but barely perceptibly, towards a triangulation of stars in the beautifully named Coma Berenices (‘Berenice’s Hair’, as celebrated in Pope’s poem ‘The Rape of the Lock’). To find something so quickly, and in such a familiar place (the Great Bear or Big Dipper being the first stop of every amateur stargazer wanting to locate the Pole Star), seemed wildly unlikely. Caroline’s Observation Book conveys meticulous caution, but also remarkable certainty.
Unable to calculate the mathematical coordinates of the object, she accompanied her observations with a series of three neat drawings or ‘figures’, over an eighty-minute time lapse. These showed the circular viewing field of her telescope, with an asterisk shape very slightly changing position relative to three known fixed stars.
August 1st 1786. 9 hours 50 mins. I saw the object in the center of fig.1 like a star out of focus while the others were perfectly clear. The sec. star is very faint but the weather is hazy, and in a clearer night undoubtedly some more will be visible…11 hours 10 mins. I think the situation is now like in Fig.3 but it is so hazy that I could only imagine I saw the second star & the preceding I could not see at all. The comet is about half way between 53 and 54 Ursa maj. and some stars which I found after looking over the map at leisure to be 14, 15, and 16 Coma Berenices…
21
Caroline does not remark that her comet was moving from a male to a female constellation, a fact which might have well have struck her as peculiarly appropriate. But the account written into the ‘Book of Work Done’ catches something of her growing excitement. The drudgery of daytime calculation in her study was overtaken by the tantalising expectations and frustrations of the nights up on the flat roof.
August 1st. I have calculated 100 nebulae today, and this evening I saw an object which I believe will prove tomorrow night to be a Comet. August 2nd. Today I calculated 150 nebulae. I fear it will not be clear tonight, it has been raining throughout the whole day, but seems now to clear up a little…1 o’clock. the object of last night IS A COMET. August 3rd. I did not go to rest till I had written to Dr Blagden [at the Royal Society] and Mr Aubert to announce the Comet. After a few hours sleep I went in the afternoon to Dr Lind, who with Mr Cavallo accompanied me to Slough with the intention of seeing the Comet; but it was cloudy and remained so all night. August 4th. I wrote today to Hanover, booked my observations and made a fair copy of 3 letters…The night is cloudy. August 5th. I calculated nebulae all day, paid the smith…The night was tolerably fine and I SAW THE COMET.
22
Both Aristotle and Galileo had thought comets were low-level atmospheric phenomena, perhaps lower than the moon. The study of comets was improved by the sixteenth-century Danish astronomer Tycho Brahe, but transformed in 1682 when Edmund Halley famously calculated that the Great Comet of that year, subsequently named after him, would reappear in 1759. It was then finally accepted that comets were outer-space objects that moved in extreme elliptical orbits round the sun, and swung far beyond the known planets. Yet they were still mysterious: of unknown origin and composition, various in their appearance, irregular and alarming in their habits. A reassuring popular view, that they were celestial table-waiters, supplying the planets with moisture and the sun with fire, was expressed by James Thomson in his poem
The Seasons
(1726-30).
From his huge vapouring train perhaps to shake
Reviving moisture on the numerous Orbs,
Thro which his long elipsis winds; perhaps
To lend new fuel to declining Suns,
To light up Worlds, and feed the etherial Fire.
23
By the mid-eighteenth century only about thirty comets had been identified and recorded in the annual French catalogue
La Connaissance des Temps.
The greatest comet-hunter of the age, Charles Messier, had personally found about half of these, and so comet-hunting was generally regarded as a French speciality. Caroline’s discovery-even if it had been her only one-would have been an important contribution internationally. Comets (meaning ‘hairy stars’) were significant because they were the only celestial objects which came in from beyond the known solar system, and therefore carried possible information about conditions further out in space.
The fact that the elliptical path of periodic comets could be calculated according to Newton’s laws, and their returns predicted scientifically, seemed to prove that their traditional role as portents of events on earth (usually of sudden disasters) was a meaningless superstition. So the comet that appears in the Bayeux Tapestry turned out to be Halley’s on a previous periodic visit; it reappeared without disaster in 1986, and is next scheduled in 2061. However, new comets such as that of 1811 still caused a great popular stir. Adam Smith noted in his
Philosophical Enquiries
(1795): ‘the rarity and inconstancy of their appearance, seemed to separate them entirely from the constant, regular, and uniform objects in the Heavens’.
24
♣
It is revealing that Caroline was too excited to sleep, and that in the absence of Herschel, almost her first reaction was to contact her friend and confidant Dr James Lind, who had spoken up for her over the treatment of her wounded leg. The note dashed off to Alexander Aubert is disarming in its modesty, but hints at her sense of obstacles overcome. ‘I hope, Sir, you will excuse the trouble I give you, with my
wag
[vague] description, which is owing to my being a bad (or what is better) no observer at all. For, for the last three years past I have not had an opportunity to look as many
hours
in the telescope. Lastly I beg you Sir, if this Comet should not have been seen before to take it under your protection.’
25
Privately she still had grave doubts about her own observation skills, and wrote a frankly unscientific ‘Memorandum’ in her Observation Book, admitting that the comet seemed to have a mind of its own, and was not behaving at all as it should. ‘I am at a loss what to think of the path which this Comet may have, by the figures [drawings] of last night it seemed to move
downwards
but tonights figures show just the contrary. In my letter to Mr Aubert I avoided taking notice of this circumstance…for my wish was only to say what was just necessary by way of delivering it into better hands.’
26
Her letter to Charles Blagden, Secretary to the Royal Society and Banks’s right-hand man, produced a dramatic reply by return of post: ‘I believe the comet has not yet been seen by anyone in England but yourself. Yesterday the Visitation of the Royal Observatory at Greenwich was held, where most of the principal astronomers in and near London attended, which afforded an opportunity of spreading the news of your discovery, and I doubt not but that many of them will verify it the next clear night. I also mentioned it in a letter to Paris, and in another I had occasion to write to Munich.’
27
The verification of Caroline’s comet was achieved much more rapidly than Herschel’s planet had been. Its movement through Coma Berenices was relatively easy to ascertain, and its fine hazy tail or coma was unmistakeable. Its cometary status was quickly confirmed by Nevil Maskelyne, and on the following evening, 6 August, an impromptu top-level deputation rode down to Slough. Caroline was astonished to receive Blagden himself, Sir Joseph Banks and the MP Lord Palmerston, demanding to see
her
comet through
her
special sweeper telescope. Gratefully, she recorded that the evening was ‘very fine’, and everyone was able to get a glorious view of the new visitor, both with her small sweeper and the higher-powered seven-foot telescope.
28
Banks was in one of his triumphal moods, and announced that her historic letter would be immediately published in the
Philosophical Transactions,
where it duly appeared-though after the usual bureaucratic delay-on 9 November, as ‘An Account of a New Comet. In a Letter from Miss Caroline Herschel’. This was her first ever publication by the Royal Society, and an almost unheard-of rarity for a female correspondent.
29
Maskelyne was also full of praise, patriotically recruiting Caroline into the new ranks of British astronomy at once. ‘I hope that we shall, by our united endeavours, get this branch of astronomical business from the French, by seeing comets sooner and observing them later.’
30
Alexander Aubert, realising the personal significance of the find for her, struck a more intimate note: ‘I wish you joy most sincerely of the discovery. I am more pleased than you can well conceive that
you
have made it-and I think that your
wonderfully clever and wonderfully amiable
Brother, upon the news of it, shed a tear of joy. You have immortalized your name.’
31
The idea of a female astronomer intrigued people. When William returned from Germany ten days later, on 16 August, he found that Caroline had become something of a celebrity. In September he was summoned to Windsor specifically ‘to exhibit to His Majesty and the royal family the new comet lately discovered by his sister, Miss Herschel’.
32
Fanny Burney the novelist, then a lady in waiting to Queen Charlotte, had evinced little previous interest in the stars. But she now suddenly discovered a lively fascination with astronomy, and leaped at the chance to abandon a game of royal piquet and join the viewing party on the Windsor terrace.
To Fanny’s disappointment, Caroline herself was not there (she avoided the Court whenever possible). But the session was interesting ‘for all sorts of reasons’, the glimpse of the comet-catcher’s brother being as fascinating as the comet. ‘We found [Herschel] at his telescope. The comet was very small, and had nothing grand or striking in its appearance; but it is the
first lady’s comet,
and I was very desirous to see it. Mr Herchel then showed me some of his newly discovered universes, with all the good humour with which he would have taken the same trouble for a brother or a sister astronomer; there is no possibility of admiring his genius more than his gentleness.’
33
Fanny was struck above all by Herschel’s total lack of arrogance: ‘he is perfectly unassuming…yet openly happy in the success of his studies’. But she wondered about his relationship with his reclusive sister.