Sunspots and Corona



Walter Maunder’s first wife had died in 1888 leaving him with a family of five children whose ages at the time of his marriage to Annie ranged from 21 down to only seven. Walter and Annie had no children of their own. No doubt the rearing of the youngest stepchildren took up a great deal of Annie’s time and energy; yet she was by no means cut off from astronomy. On the contrary: she carried on her editing of the Journal of the British Astronomical Association and soon found herself preparing to accompany her husband on an expedition to Norway to observe the total solar eclipse of 9 August 1896.

Maunder was an experienced eclipse observer, having taken part in an official British expedition in August 1886 to the tiny island of Carriacou in the West Indies where he obtained a series of photographs of the corona. The scientific authorities in Britain gave high priority to eclipse observations: a national Eclipse Committee, on which the Royal Observatory Greenwich was strongly involved (Maunder himself was a member), was responsible for financing and organising expeditions, and observers such as Maunder would be directed to travel and carry out observations as recommended by that Committee. For the 1896 eclipse, an independent expedition was organised by the British Astronomical Association for its amateur members and their friends, the first such venture by that society (Chapter 10). Annie’s doctor brother accompanied them as a helper. The eclipse was unfortunately clouded out at their station at Nova Zembla, but the expedition was long remembered as an outstanding social successii (and resulted in two romances – the Roberts’, already mentioned, and the Eversheds’, to be described later).

Walter Maunder was a widower approaching 45 years of age when he married his young assistant Annie Russell, aged 27, whom we have met in the previous chapter (Fig. 14.1). The romance of close colleagues who worked so well together was perhaps inevitable. Walter, to judge from his photographs, was a handsome man, and, according to his friends, one of amiable personality, “a generous-minded gentleman, one who never willfully said an unkind word but often said kind ones.”i They also shared a deep Christian faith. Both were children of evangelical ministers, Walter’s father being a Wesleyan pastor. The couple were married in the Presbyterian Church, Greenwich on 28 December 1895.
Fig. 14.1

Annie Maunder. (Armagh Observatory)

Walter Maunder’s first wife had died in 1888 leaving him with a family of five children whose ages at the time of his marriage to Annie ranged from 21 down to only seven. Walter and Annie had no children of their own. No doubt the rearing of the youngest stepchildren took up a great deal of Annie’s time and energy; yet she was by no means cut off from astronomy. On the contrary: she carried on her editing of the Journal of the British Astronomical Association and soon found herself preparing to accompany her husband on an expedition to Norway to observe the total solar eclipse of 9 August 1896.

Maunder was an experienced eclipse observer, having taken part in an official British expedition in August 1886 to the tiny island of Carriacou in the West Indies where he obtained a series of photographs of the corona. The scientific authorities in Britain gave high priority to eclipse observations: a national Eclipse Committee, on which the Royal Observatory Greenwich was strongly involved (Maunder himself was a member), was responsible for financing and organising expeditions, and observers such as Maunder would be directed to travel and carry out observations as recommended by that Committee. For the 1896 eclipse, an independent expedition was organised by the British Astronomical Association for its amateur members and their friends, the first such venture by that society (Chapter 10). Annie’s doctor brother accompanied them as a helper. The eclipse was unfortunately clouded out at their station at Nova Zembla, but the expedition was long remembered as an outstanding social successii (and resulted in two romances – the Roberts’, already mentioned, and the Eversheds’, to be described later).

Another opportunity to observe a total solar eclipse arose on 22 January 1898, this time in India (Fig. 14.2). Annie offered some hints for observers in the pages of the Journal of the British Astronomical Association,iii recommending suitable tents and equipment, doubtless advised by her sister who was a doctor in Poona. Maunder was not a designated member of the official British expedition on this occasion. He and Annie made their own private arrangements,” hampered by no restrictions whatsoever, having received absolutely no financial help from any public body.”iv With other observers from the British Astronomical Association, they had their site at Talni, a village in the Hyderabad District. They were favoured with excellent weather and reported their results in a charming illustrated book brought out by Walter Maunder on their return.v
Fig. 14.2

Annie Maunder and eclipse observers in India, January 1898. (Institute of Astronomy, Cambridge)

The Maunders each had their separate apparatus of which Annie’s produced the more original and far-reaching result. She had two cameras. One was of 2.5 in. (6 cm) aperture and focal length of 8 ft (2.4 m) mounted equatorially and driven by a clock. This compact and portable outfit, which Annie had seen in Norway on the 1896 clouded-out expedition, had been bequeathed to the Royal Astronomical Society by its owner, an amateur Fellow, and was lent to her by the Society. Annie mounted the second camera on the opposite side of the axis in place of the counterweight. (A telescope attached to one side of the axis of a mounting is normally balanced by a metal weight on the other side). This was a short-focus camera with a lens of only 1.5 in. (3.8 cm) diameter and 9 in. (23 cm) focal length which she had bought with a research grant from her Cambridge College. Its exquisite lens was made by the world-renowned London optician, T.R. Dallmeyer, well-known for his beautiful camera lenses including the telephoto lens which he inventedin

Annie originally planned this special small camera for wide angle photography of the Milky Way. It had a field of view of over 40 degrees and would span the entire width of the belt. Photography of Milky Way panoramas was popular ever since the American astronomer Edward Emerson Barnard at Lick Observatory had tried a portrait lens on the sky in 1889, and expert astronomical photographers like Isaac Roberts were now producing stunning photographs of star clouds and nebulae. A serious challenge for all such astronomical optics was how to achieve sharp images at the outer parts of the field of view (the problem was eventually solved with the invention of the Schmidt telescope in 1930); the special high quality Dallmeyer lens which Annie acquired lost very little definition at the edges of the photograph. Long exposures were required, however, to show up images of faint stars, and a dark clear moonless sky was needed to prevent fogging of the photographic plate from background “light pollution”. The eclipse expedition was an opportunity to try her Milky Way photography under clear Indian skies.

In the moonfree nights before the eclipse, Annie worked while other obser-vers slept. The Zodiacal Light was visible for the first hour or so after sunset (the Maunders tried to photograph it without success) so Annie waited until the dead of night before beginning her solitary vigil. During the four-and-half hour exposures that were needed, the driving clock had to be wound every half-hour, and a constant eye kept on the guiding star by Annie, slow motion rods in hand to correct for the clock’s imperfect movement.vii (These Indian photographs were not published but another excellent photograph of a Milky Way field taken by Annie in August 1900, perhaps in Algiers after the eclipse there, was reproduced in the Maunders’ book The Heavens and their Storyviii).

For the actual eclipse, Annie’s plan was to take a series of photographs of the corona with each of the cameras, with exposures ranging from one to twenty seconds, which would cover a large range of brightness. She also varied the type of photographic emulsion. She herself operated her own new camera while a colleague from the British Astronomical Association operated the other. All was accomplished within the few minutes of totality. Some of the photographs she deemed “very successful”, in particular those taken with her own small instrument which covered a large span of sky. One of these, centred well to one side of the eclipsed Sun, showed a streamer emanating from the corona which she described as “rod-like” extending to 10 million kilometres or 14 solar radii, by far the longest extension of the corona yet recorded, which was published in popular articles by Walter (under his own name).ix When the results of the various British expeditions were displayed at a Royal Society soirée Agnes Clerke, whose reports were highly respected, gave her verdict:” As regards the corona, Mrs. Maunder with her tiny lens has beaten all the big instruments”. She reproduced this striking photograph (Fig. 14.3) in her well-known book Problems in Astrophysics (1903)x (as did Robert Ball in a new edition of his popular Story of the Heavens in 1901), but later writers appear to have overlooked this remarkable observation. The original drawing made from this historic photograph is preserved in the High Altitude Observatory in Boulder, Colorado. Only in recent years has its significance come to be appreciated by solar and geo-physicists (as is discussed later).
Fig. 14.3

Annie Maunder’s “Longest Ray” 1898. (High Altitude Observatory, Boulder)

The Maunders took part in two further eclipse expeditions, in quick succession, both favoured with clear skies. In Algiers in May 1900, as members of a large contingent from the British Astronomical Association, they were accompanied by Maunder’s two daughters, then in their early twenties. Annie collaborated with her husband who used a small telescope of his own, a 4-in. refractor, to take photographs of the corona. A year later, in Mauritius in May 1901, Walter was sent as an official observer, equipped with Greenwich instruments to be used as instructed. He had hoped that Annie might be included as an official member of the Greenwich team; he raised the matter with the secretary of the Committee who seemed to be sympathetic, but, after much correspondence, the Maunders appear to have let the matter drop to avoid the embarrassment of a refusal.xi Annie nevertheless accompanied her husband at her own expense, and made her own entirely independent plans. They even observed from different locations. Annie’s site was at the meteorological observatory at Pamplemousses, the same which supplied Greenwich with daily photographs of the Sun, where she had the help of the assistant astronomer there. She had brought her cherished small camera, intending to repeat the Indian programme – photographs of the southern Milky Way and of the outer parts of the corona – but encountered a serious drawback in the humid climate. Long exposures at night were impossible: the lens kept dewing up with moisture and had to be wiped every few minutes. She therefore got no Milky Way photographs, and only one short exposure of the corona. However, she had another instrument to fall back on – a camera lent by an amateur friend, G.J. Newbegin, with which she obtained a number of excellent photographs of the inner regions of the corona which had the characteristic round shape found in times of sunspot minimum, and showed a most delicate pattern of plumes and prominences.xii Two of the Mauritius corona photographs, an official one by Walter and an unofficial one by Annie, were included much later in the published record of the eclipsexiii, xiv; Annie’s is distinctly superior in its remarkable detail.

The next suitable eclipse, in August 1905, passed over Canada, Spain and North Africa. The Maunders were invited by the Canadian Government to join its expedition to Labrador where it was planned that Annie, specifically, should employ a corona camera identical with that being used by the official British expedition in Egypt. The purpose was to verify that the corona is truly attached to the main body of the Sun by comparing its appearance at the two extremities of the eclipse path which were separated by a significant interval of time. A difference would be expected on account of the rotation of the Sun. Unfortunately the Canadian expedition was completely frustrated by clouds. It is worth noting that this was the only expedition on which Annie’s expenses were paid – by the Canadian Government. Her excellent contributions to British astronomy in India and Mauritius were made at her own expense.

The principal contributions to solar physics associated with the name of Maunder are the analysis of the cyclical variation in sunspot latitudes, the discovery of a 27-day periodicity in terrestrial magnetic activity, both published in 1904,xv and the nature of the connection between large sunspots and strong magnetic storms. Annie was Walter’s partner in these researches some of which were published under their joint names.

The 11-year cycle of sunspot numbers was established in the middle of the nineteenth century, and gave rise to a great interest in observing the Sun, including the establishment of the solar department in Greenwich under Maunder in 1873. It was found that sunspots never appeared on the Sun’s equator or at its poles but were confined to a belt of about 30 degrees in latitude, between about 5 and 35 degrees north and south of the equator. The apparent movement of individual spots across the face of the Sun showed that the Sun rotated faster near the poles than at the equator, demonstrating that it was not a solid body. The spots themselves also tended to drift, a fact first noticed during the sunspot cycle of the 1860s by more than one solar observer. Accumulated records over many years also brought to light the fact that the favoured latitudes of spots changed steadily as the cycle advanced. Agnes Clerke summed up the general conclusions in 1902: “It may now be looked upon as established that the spot zones close in towards the equator with the advance of each cycle, their activity culminating as a rule at a mean latitude of about 16 degrees and expiring when it is reduced to 6 degrees. Before this happens, however, a completely new disturbance will have manifested itself some 35 degrees north and south of the equator, and will have begun to travel over the same course as its predecessor. Each series of spot is thus, to some extent, overlapped by the succeeding one”.xvi

The analysis of the unrivalled Greenwich data, extending from 1877 to 1902 – more than two whole cycles – put these ideas on a firm basis. The Maunders plotted on graph paper the latitude of each individual spot against the date of observation – one calling out the numbers, the other plotting. They did this together at home, as Annie recalled many years later:” We made this diagram in a week of evenings, one dictating and the other ruling these little lines. We had to do it in a hurry because we wanted to get it before the [Royal Astronomical] Society at the same meeting as the other sunspot observers, whose views we knew to be heretical. As it turned out  the diagram wiped the other papers clean off the slate.”xvii The striking diagram was more illuminating than a thousand words. The distinctive progress of the cycle was plain to see – the spots’ upward drift in latitude as the cycle progresses, and the beginning of a fresh cycle before the old one vanishes. The same butterfly-shaped pattern repeats itself as records accumulate: today, a century later, a dozen “butterflies” have duly been born and passed on. It is one of the best known and delightful diagrams in astronomy.

The Butterfly Diagram (Fig. 14.4) was published in a paper by Walter Maunder in 1904, and is generally attributed to him alone.xviii It has taken 100 years for Annie’s part in constructing it to become known through the efforts of Dr. Tom Bogdan of the High Altitude Observatory, Boulder, who had the original drawing restored and its history revealed in 2000, as is told in more detail later. Walter (it is not known if Annie was involved in this work also) followed up another remarkable fact noted by an earlier observer, the persistent and patient German astronomer Gustav Spörer. Spörer, an early observer of the sunspot latitude drift, noted that for a period of about 70 years previous to 1716, sunspots and aurorae had been extremely rare or, as he preferred to describe it, the sunspot cycle was submerged. This calm interlude is now known as the Maunder Minimum.
Fig. 14.4

The original Maunder Butterfly Diagram. (High Altitude Observatory, Boulder)

That there was a general correlation between sunspots, aurorae, and disturbances in the Earth’s magnetism had long been known. In addition, extra strong magnetic effects (magnetic storms) caused by individual large sunspots were observed on a number of occasions in the nineteenth century. Annie had witnessed an especially dramatic example in February 1892 soon after she took up her post at Greenwich. A huge sunspot was seen close to the centre of the Sun’s disk. The magnetic instrument at Greenwich and at magnetic stations worldwide vibrated wildly, and that same night there was a brilliant aurora seen over many parts of the globe. The cause of such an event – though not universally accepted until the end of the century – is that the Sun spews out from the sunspot or its neighbourhood a stream of electrically charged particles which, on passing close to the Earth several hours later, spiral down towards the Earth’s magnetic poles. The moving charged particles themselves have their own magnetic influence, and thus disturb the magnetic compass needle which, in quiet circumstances, would point towards the north magnetic pole. Simultaneously, on ploughing through the atmosphere, they cause the air in the upper regions to glow, giving rise to the beautiful spectacle of the aurora in high northern and southern polar latitudes. (The detailed physics behind these phenomena is extremely complex, and is still the subject of much research). The Maunders could point out that large spots did not always produce magnetic storms, and that, conversely, magnetic storms sometimes occurred without a conspicuous spot. Here is Annie’s explanation:

“On a particular region of the sun some commotion occurs: sunspots, faculae, prominences are formed; above the disturbed area a great petal-like streamer of corona arises, its apex drawn out into a rod-like ray, which extends from the sun to distances which may be expressed in scores or hundreds or millions of miles. In these rays the particles, whatever their nature, are now not connected with the sun, though they once were; each still keeps the direction and motion which it had when it left the sun. The sun may go on spouting a coronal stream from the same region for months at a time, and in this region spots may break out and die, and again break out; for sunspots are but one symptom of the sun’s activity, and perhaps not even the most important one. As the earth moves round the sun, which is himself turning on its axis, the same long stream may strike and pass it, may strike and pass again month after month, for many months at a time; or perhaps it may sometimes strike and sometimes miss.”xix

This picture of the Sun’s activity also explains another important discovery made by the Maunders – recurring magnetic storms in 27 day cycles. As seen from the Earth the Sun spins on its axis once in 27 days, bringing a disturbed area on the Sun round to face the Earth with that frequency, even though nothing special may be visible. The Maunders concluded that the culprit source was not on the Sun’s obvious face but in the corona. They were entirely right. Their insights were years ahead of their time. It is only in recent decades that the Maunders’ contribution to the understanding of the relations between solar and terrestrial phenomena are being reassessed and appreciated.xx

The book just referred to, The Heavens and their Story, was published nominally by the two Maunders in 1910, Annie’s name appearing as the first author on the title page.xxi This delightful book, a model of what a science book for the general reader ought to be, displays Mrs. Maunder’s own style and interests. In the space of a few hundred pages the essentials of astronomy and astrophysics are lucidly expounded. The highly readable text is spiced with literary quotations and imaginatively illustrated with photographs and drawings, including Annie’s own photographs of the solar corona taken in India and at Mauritius. On the subject of the planets, the much discussed canals of Mars were given short shrift: both Maunders took their stand against the proposition that there were man-made water-carrying structures on our neighbouring planet. Annie Maunder elaborated on these deceptive Martian features in a separate article.xxii

In a Preface, Maunder states that the book ”which stands in the joint names of my wife and myself, is almost wholly the work of my wife, as circumstances prevented me taking any further part in it soon after it was commenced”. One may well ask why, that being the case, the husband could not have allowed the wife to publish entirely in her own name. It may have been for commercial reasons: his name was better known. But one suspects that it was part of the ethos of the day, when women knew their place as their husband’s subordinates, though in the Maunders’ case, the wife was academically the more qualified. Indeed, Annie’s scientific career was in a way hampered by her husband, who had become somewhat disenchanted in his post at Greenwich. He had been in the same rank, with no prospects of further promotion, since his appointment 30 years earlier, while smart younger men, with university degrees, overtook him. He built an empire of his own among the amateur astronomers in the British Astronomical Association, in which Annie joined him. One result was that Annie’s eclipse observations were published under Walter’s name in popular journals rather than broadcast throughout the professional community in Monthly Notices of the Royal Astronomical Society. Not being a herself a Fellow of the Society, she was unable to submit her work there on her own account. Some professional scientists, such as Turner, the Chief Assistant at Greenwich, ignored the amateurs altogether.xxiii Yet, as Marilyn Ogilvie, a modern historian of astronomy and an admirer of Annie, points out, a career as an “obligatory amateur” was the only one open to her, and she made the most of it.xxiv She had, of course, the advantage over other amateurs that the Greenwich solar records were available to her. She published in an Appendix to the Greenwich Observations of 1907 an analysis of over 600 sunspot groups compiled from those records since their inception, which was not perhaps adequately valued at the time.

Walter Maunder retired in 1913 after 40 years of service. In 1914 the first World War broke out, and the Royal Observatory, in common with many institutions, found itself short of staff as its male workers left on active service. In 1916 Walter Maunder was recalled to his old post in charge of the Greenwich sunspot records. His wife joined him as a volunteer (i.e., without salary).xxv The Maunders kept up the solar work until 1920, well after the end of the war. These were surely happy years for them, as they resumed their old routines of 20 years earlier. The observatory was now under a different Astronomer Royal, Frank (later Sir Frank) Dyson, a man well known for his charm and friendly personality, with whom the Maunders felt at ease. They already knew him, as he had been Chief Assistant at Greenwich before taking up his previous appointment in Edinburgh. He was the same age as Annie, and his wife, a classicist, had been her student contemporary at Girton College, Cambridge.

In December 1914, when the ban on women Fellows of the Royal Astronomical Society was about to be lifted, Dyson invited her to put her name forward. Annie had not forgotten the earlier snub in 1892, when she and her two friends were proposed and rejected. She wrote thanking him, and continued xxvi:

“But 22 years ago I was brought forward as a candidate for Fellowship in company with two other women, – one of whom, Elizabeth Brown, is now dead, – in just this way. The Society then declined to express a corporate opinion on the eligibility of women for Fellowship until some women had actually presented themselves for election. The election went against us. Of course, I recognise, and have done so all along, that the Society is perfectly within its right and competence to restrict its Fellowship as it deems fit; in other words, I feel that women cannot claim the election of women as a right, and I am sure that our rejection was not intended to convey the slightest discourtesy to us, either as women or as individuals. But just for these very reasons, I am bound to accept the decision then given, as far as I am concerned. If the Society should see fit, – seeing that I have already once applied, – to reverse its former decision, and grant me admission without further application, I should value it exceedingly.

I have much appreciated the courtesy and honour which the Society has shown me, in inviting me to attend its meetings as a guest. This was a gift on the part of the Society, and I have gratefully accepted it for 22 years. If now, of its own initiative, it were to give me what it refused me before, that would be a gracious act. But if I make a second application for it, it would imply that I was dissatisfied with what has already been done for me; and further, if I were again blackballed – as might well be the case – I should feel that I had placed myself in quite a false position”.

Behind the polite words lurks Annie’s bitterness at her second-grade status among the professionals. Her suggestion was followed, and she was elected in 1916 on the reactivation of her husband’s original nomination. The episode brought an unexpected revelation. Dyson’s proposal to nominate her was supported by H.H. Turner, the same powerful figure who had been so dismissive, almost rude, when she applied for her “lady computer” post all those years ago, who made no secret of the fact that he disapproved of amateur science, and whom her husband mistrusted. She admitted to Dyson: “I appreciate the more highly the offer of his present support, because I had formed the impression, whether correct or not, that he had blackballed me on the former occasion”.

A subject which Annie Maunder was to make very specially her own – the history of ancient cosmologies – first makes its appearance in her husband’s book, The Astronomy of the Bible, published in 1908.xxvii Both the Maunders were deeply versed in the writings of the sacred scriptures, and in 1923 Annie was awarded a prize by Girton College Cambridge for an essay on a biblical topic.xxviii The book discusses and explains numerous astronomical allusions in the Old Testament, and is reported to have earned the commendation of the Rabbi, the Pope and the Archbishops of Canterbury and York.xxix

Among astronomical matters examined by the Maunders was the origin of the constellations. From a study of the uncharted regions of the southern sky on early celestial charts the position of the south celestial pole could be deduced as could the geographical latitude of the mapmakers’ location. Taking precession into account, the date of the first mapping of the constellations was calculated to have been made about 2700 BC from a place of latitude about 37 degrees north. This was the first serious attempt to work out this interesting

In 1910 the Maunders wrote a joint paper on the origin of the planetary symbols, an interest triggered by their study of old astronomical texts in the library of the Royal Observatory at Greenwichxxxi Virtually all of Annie Maunder’s later work was dedicated to researches of a similar kind. She made a detailed study, using translations, of astronomical allusions in Iranian and Indian sacred texts in a lecture delivered to the Victoria Institute in London in 1916.xxxii The Victoria Institute, which still flourishes, was founded in 1867 to examine the relation between science and religion from the Christian point of view; with a membership of 600 men and women, the Institute had many distinguished scientists in its ranks including the astronomers Sir David Gill and Sir Frank Dyson. E.W. Maunder was the secretary. Being a reluctant public speaker Mrs. Maunder’s lecture was delivered by her husband while Sir Frank Dyson, the Astronomer Royal, took the chair. Her paper displays a vast amount of research in what was then a little-studied field. She also looked into cometary records in the writings of the seventeenth century English traveller and explorer Peter Mundyxxxiii and wrote an astronomical appendix to a new printing of his travels. As late as 1936 she returned to the subject of the origin of the constellations in a paper in the Observatory where she revised her estimated date of their establishment to 2900 ± 100 BC,xxxiv a date which agrees well with modern opinion. The large volume of her historical work put Mrs. Maunder ahead of her time in the now popular field of ancient and archaic astronomy. In her lifetime she was looked upon as an expert on this subject; like her eclipse observations, her efforts may not have been sufficiently appreciated by later generations.

Maunder died in 1928 after a long illness. Annie, though bereft of her partner of 33 years, continued to devote herself to the work of the British Astronomical Association and to her historical researches. She also wrote numerous popular articles on astronomy.xxxv The years of the Second World War were stressful, but she and Mrs. Evershed (next chapter) responded to a request to write a history of the British Astronomical Association which was now half a century in existence. It was “a long and difficult matter”,xxxvi but was accomplished. Annie, aged 74, read her paper on 30 September 1942.xxxvii She recollected their first meeting and the spirit of the Association which she herself did so much to sustain: “Men and women astronomers came in on equal terms; so also with the rich and the poor; those who worked with their hands and those with their heads; and all pooled their varying knowledge for the public good.”

An event that gave Annie great pleasure in later years was her association with the solar High Altitude Observatory in Colorado to which she donated the original Butterfly diagram and a reproduction of her “Longest Coronal Ray”. The chain of events that led to this began in 1937 when she received a request from an amateur astronomer in USA for permission to copy a certain illustration from Maunder’s Astronomy of the Bible. She gladly agreed – incidentally discovering that the book in her correspondent’s possession was a pirated edition of which she knew nothing.xxxviii An exchange of letters followed, and in 1941, when war conditions in London were grim, Annie decided to send the original Butterfly Diagram for safe keeping to her American friend. He in turn, with Annie’s permission, gave it on long-term loan to the High Altitude Observatory in Climax, Colorado, in the care of Walter Orr Roberts, then a young solar physicist.xxxix “I am especially glad”, Annie wrote to Roberts in 1943, “to get the “Butterfly” into a safe and kind home  . I am tempted to ask you to take in another “evacuee”. It is the enlarged drawing made by the late Mr. Wesley of my “Longest Coronal Ray”, which I photographed during the eclipse of 1898 January 22 in India”.xl Both these historic drawings are now lovingly preserved in the High Altitude Observatory.

In the same year, Annie had the satisfaction of listening to Sydney Chapman, President of the Royal Astronomical Society, who chose the Butterfly Diagram as the subject of his 1943 Presidential address (the actual title was “Magnetism in the Earth’s atmosphere”). Chapman was a key thinker in the interpretation of magnetic storms in terms of particles emanating from the Sun, a problem for which the Maunder diagrams were highly relevant. His work led in 1955 – though Annie did not live to hear it – to Eugene Parker’s solution of a hot corona and the solar wind.

The Maunders’ conclusions regarding the influence of the Sun’s activity on earthly disturbances were revisited and confirmed by the American solar physicist John Eddy who in 1975 renamed the prolonged dearth of sunspots in the eighteenth century the “Maunder Minimum” in his honour (or in honour of the couple). The expression has entered the language. No doubt this naming was done with the best intentions; but one wonders by what right a scientist may deprive someone of an earlier age of his priority, in this case Gustav Spörer, acclaimed by Maunder himself as the discoverer of the historic phenomenon now bearing the latter’s name.xli (Spörer has been given the consolation prize of an earlier, shorter, sunspot lull.)

Annie survived her husband by almost 20 years, and at the end of her long and active life had a home close to her brother’s in Surrey. She died on 15 September 1947 in her 18th year. The Maunders are individually commemorated by craters on the Moon – a unique case for a couple. Annie herself would probably choose to be remembered by her most cherished pieces of work – the Butterfly Diagram and the Longest Coronal Ray.

14.1 Notes

iH.P. Hollis. Obituary, Journal of the British Astronomical Association, May 1928, 229–233.

iiR.A. Marriott. 1991. JBAA101, 162.

iiiA.S.D. Russell, 1895. JBAA3, 29.

ivE.W. Maunder 1898. Observatory21, 279.

vE.W. Maunder 1898. The Indian Eclipse 1898, Hazell, Watson and Viney, London.

viHenry C. King. 1979. The history of the telescope. New York: Dover Publications (reprint), p 273.

viiA.S.D. Maunder. 1898. Some photographs of the Milky Way and of the solar corona of January 22, 1898. The Girton Review50, 1–6. August 1898.

viiiAnnie S.D. Maunder and E. Walter Maunder. 1910. The Heavens and their Story. London: Charles H. Kelly.

ixE.W. Maunder, 1899. Observatory22, 315. The photograph was also published the magazine Knowledge, and in the Maunders’ book.

xAgnes M. Clerke. 1903. Problems in Astrophysics, Adam and Charles Black, London.

xiM.B. Ogilvie, 2000. Obligatory Amateurs. British Journal for the History of Science33, 67–84.

xiiReproduced in the Maunders’ book, op. cit.

xiiiF.W. Dyson and W. Christie. Memoirs RAS64,1925–29; reprinted in W.W.-H. Soon and S.H. Yaskell, 2003. The Maunder Minimum and the Variable Sun-Earth Connection. p 157. Singapore: World Scientific.

xivM.T. Brück. 1994. Alice Everett and Annie Russell Maunder, torch bearing women astrono-mers. Irish Astronomical Journal21, 281–90.

xvE.W. and A.S.D. Maunder. 1905. Monthly Notices of the Royal Astronomical Society65, 2–34 and 813.

xviAgnes Clerke. 2003. History of Astronomy (reprint edition), p 148.

xviiAnnie Maunder. Letter to a friend to whom she gave the diagram in 1940. Archives of the High Altitude Observatory, Boulder, Colorado. Courtesy Dr T. Bogdon.

xviiiFor example in H.W. Newton. 1958. The Face of the Sun, 51–52. Penguin Books. Newton was a successor of Maunder as head of the Solar Department at Greenwich.

xixAnnie S.D. Maunder and E. Walter Maunder. 1910. The Heavens and their Story. op. cit.

xxWillie Wei-Hock Soon and Steven Yaskell. 2004. The Maunder Minimum and the Variable Sun-Earth Connection. Singapore: World Scientific.

xxiAnnie S.D. Maunder and E. Walter Maunder. 1910. op. cit.

xxiiA.S.D. Maunder, 1907. Knowledge4, 169.

xxiiiM.T. Brück. 2002. Agnes Mary Clerke and the rise of Astrophysics, Chapter 13. Cambridge University Press.

xxivMarilyn Bailey Ogilvie. 2000 Obligatory amateurs: Annie Maunder (1868–1947) and British women astronomers at the dawn of professional astronomy. British Journal of the History of Science33, 67–84.

xxvRoyal Observatory Greenwich, 1916 et seq. Annual Reports to the Board of Visitors.

xxviMrs A.S.D. Maunder to Dyson. 1914 December 4. RGO 8/150.

xxviiE. Walter Maunder FRAS, 1908 (Fourth edition 1922). The Astronomy of the Bible. London: The Epworth Press.

xxviiiGirton College Report 1923. The prize, founded in 1889 by Mrs Y.J. Gibson, was for the best essay on a subject connected with the Greek testament.

xxixH.P. Hollis, 1928. Obituary of E.W. Maunder. Observatory38, 229.

xxxAlex A. Gurshtein. 1993. Vistas in Astronomy36, 171.

xxxiE.W. Maunder and A.S.D. Maunder. 1920. JBAA30, 219.

xxxiiA.S.D. Maunder. 1915. On Astronomical Allusions in Sacred Books of the East, Journal of the Transactions of the Victoria Institute47, 181–232. A popular account appeared in Observatory39, 48.

xxxiiiA.S.D. Maunder. 1934. Observatory57, 279. The work was done for the Hakluyt Society, a society dedicated to publishing rare or unpublished voyages and travels, named after a famous 16th century historian of discoveries, Richard Hakluyt.

xxxivA.S.D. Maunder. 1936. Observatory59, 367.

xxxvAnthony Kinder who is writing a biography of Walter Maunder has a collection of magazine articles.

xxxviA.S.D. Maunder to Roberts. 1943 July 17. Archives of the University of Colorado at Boulder Libraries. Annie’s wartime worry, as she mentioned in a letter to Roberts, was on behalf of her cousin who was on active service. The cousin was Field Marshall Sir John Dill, sent by Churchill in 1941 to Washington as his representative on the American Joint Chiefs of Staff. He died before the end of the war and was accorded burial by President Roosevelt in Arlington Cemetery, “the only foreigner to be so honoured.” (David Stafford. Roosevelt and Churchill, men of secrets. 1999. p 128. London: Little, Brown and Co.).

xxxviiA.S.D. Maunder. 1943. Reminiscences of the British Astronomical Association, Journal of the British Astronomical Association42, 268.

xxxviiiMaunder Family papers. I thank Anthony Kinder for kindly showing me these letters.

xxxixW.O. Roberts correspondence, Archives of the University of Colorado at Boulder Libraries. Courtesy T.G. Bogdon.

xlA.S.D. Maunder to Mr and Mrs Roberts. 1942 November 19. Archives of the University of Colorado at Boulder Libraries. Courtesy T.G. Bogden.

xliAgnes Clerke, following Maunder, states that Spörer’s researches showed that the sunspot cycle “was in abeyance during some seventy years previously to 1716, during which period sun-spots remained persistently scarce, and auroral displays were feeble and infrequent even in high northern latitudes. An unaccountable suspension in solar activity is, in fact, indicated”. (History op. cit., p 148).

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  1. 1.PenicuikUnited Kingdom

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