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The Role of Images in Astronomical Discovery

Page 7

by Rene Roy


  a distance of 10.3 light-years.37

  Secondly, to conduct his many survey programs, Herschel used several telescopes of

  his making. His favorite was a 20-ft focal length telescope equipped with an 18-inch

  metal mirror (Fig. 1.6); it was his most versatile and used instrument. Most importantly,

  37 Friedrich Wilhelm Bessel, Friedrich Georg Wilhelm von Struve (1793–1864) and Thomas James Henderson (1798–1864) measured stellar parallaxes almost simultaneously. Bessel had made the most extensive measurements; he received the Gold Medal of the Royal Astronomical Society in 1840. For a fine historical description, see A. Hirshfeld, Parallax: The Race to Measure the Cosmos, New York: W. H. Freeman and Co., 2001.

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  Part I – Images and the Cosmos

  Herschel’s telescopes were innovative and better than all others. The 20-year research pro-

  gram of William Herschel was a major accomplishment in the history of astronomy: best

  telescopes, best observers and best observing programs.

  Perfectly Milky, Absolutely Irresolvable

  The Herschels had turned an important page of nebular research, having identified and

  registered close to 2,500 “nebulae” and star clusters. Their work published in the Philo-

  sophical Transactions of the Royal Society of London greatly surpassed in number and

  quality of data what had been observed before.38 Herschel’s Catalogue of One Thousand

  new Nebulae and Clusters of Stars, later completed and published by Caroline, became

  the pillar of several other research programs that followed over the years, first that of his

  son John Herschel (1792–1871). These resulted in the General Catalogue of nebulae and

  clusters of stars (1864) and, in 1888, the New General Catalogue (NGC) by Danish-born

  Irish astronomer John Louis Emil Dreyer (1852–1926): the well-known NGC is the basis

  of today’s galaxy catalogues.39 Successive observers contributed to these catalogues.40

  They were based on visual telescopic observations, supplemented with written notes and

  descriptions. The observers often included hand-drawn sketches for the more spectacular

  or unusual objects (Chapter 2).

  Descriptive observations of nebulae continued with John Herschel. John was the son

  of William Herschel and Mary Baldwin whom William had married in 1788. Educated at

  Eton College and St John’s College, Cambridge, John’s training had followed a much more

  scholarly path than that of his father or aunt Caroline. John received solid professional train-

  ing. He turned out to be a versatile scientist, at ease with natural philosophy, mathematics

  and chemistry as well as astronomy.

  John Herschel understood the importance of images, and took great care to make his

  several drawings as faithful to the true appearance as possible.41 Although he did not appear

  to have tried to photograph nebulae, he later made important contributions to photography

  as a general technique. Writing in 1826, the young Herschel described the “great nebula”

  in Andromeda as “optically nebulous, owing to the smallness of its constituent stars. . . . Its

  nebulosity is of the most perfectly milky absolutely irresolvable kind, without the slightest

  tendency to that separation into flocculi above described in the nebula in Orion, nor is there

  any sort of appearance of the smallest star in the centre of the nipple. This nebula is oval,

  very bright, and of great magnitude, and altogether a most magnificent object.”42

  38 H. Nussbaumer and L. Bieri, Discovering the Expanding Universe, Cambridge: Cambridge University Press, 2009, p. 35.

  39 W. Steinicke, Observing and Cataloguing Nebulae and Star Clusters: From Herschel to Dreyer’s New General Catalogue, Cambridge: Cambridge University Press, 2010.

  40 For a summary of catalogues of galaxies, see H. G. Corwin Jr., Galaxy Catalogues and Surveys, in The World of Galaxies, H.

  G. Corwin Jr. and L. Bottinelli (editors), New York: Springer, 1989, pp. 1–15.

  41 O. W. Nasim, Observing by Hand: Sketching the Nebulae in the Nineteenth Century, Chicago: University of Chicago Press, 2103, pp. 123–170.

  42 J. F. W. Herschel, Observations of Nebulae and Clusters of Stars, Made at Slough, with a Twenty-Feet Reflector, between the Years 1825 and 1833, Philosophical Transactions of the Royal Society of London, 1833, Vol. 123, pp. 359–505.

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  As better instrumentation became available, the “nebulous cloud” of Andromeda drew

  more attention, this time from an observer in North America, where astronomical research

  was just taking its first steps at a preeminent American institution. Succeeding his father

  William Cranch Bond (1789–1859), American astronomer George Phillips Bond (1825–

  1865) became the second director of Harvard College Observatory. The younger Bond was

  an expert in comets, discovering ten of them. Of a broad approach in his research, Bond

  jumped on the opportunity to use the recently installed 15-inch “great refractor” of the

  Cambridge Observatory to view “nebulae.” He did so with mastery. I will describe his work

  in more detail in the next chapter.

  In the midst of the nineteenth century, astronomers were battling with “scrambled crazy

  images of things recently seen” as the words of Edward O. Wilson remind us. Patterns

  were emerging, but hypotheses were flimsy and shaky, as illustrated by William Herschel’s

  swinging views on the nature of “nebulae.” However, the process of systematic observing

  and cataloguing of “nebulae” set the path to the building of a solid database and for more

  systematic surveys. New experiments and ambitious programs were set up to pursue the

  chase. More rigorous approaches were taken for recording images, not just in words. Let

  us now see how drawing and sketching helped make progress in unraveling the mystery of

  “nebulae.”

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  Portraying Cosmic Whirlpools

  It is hard to learn to paint dirt. I painted the surface in reddish tones, but

  it looks now too much like Mars to me. And I’ve tried blue and purple,

  but then it looks like the Antarctic. Monet never paints dirt.

  Alan Bean

  Still in our climate, where there is so much cloudy weather, a year’s

  work, measured by the number of hours when nebulae can be effectively

  observed, is not considerable.

  William Parsons, Third Earl of Rosse 1

  In becoming familiar with something, one is on the way to becom-

  ing acquainted with its nuances, peculiarities, properties and possible

  nature.

  Omar W. Nasim 2

  Can One Draw Objects without a Clue of What They Are?

  American astronaut Alan Bean was a member of the Apollo 12 mission and of the second

  team to land on the Moon in November 1969. When he retired from NASA in 1981, he

  devoted himself to painting manned missions to the lunar surface. Although photographs

  showed the lunar surface to be dull gray, Bean gave it impressionistic tones with colours

  that reproduced the Moon environment that the astronauts experienced, “a brightly lit space

  where heat from the Sun is palpable.”3 Bean’s inspiring and dramatic paintings are a twenty-

  first-century expression of a prevailing way of representing nature, by
drawing it and paint-

  ing it. He is an artist of nature with the eye of a scientist conveying the subtleties and

  challenges of depicting real objects through images.

  Drawing, sketching and portraying have been part of the process of scientific description

  and communication for centuries. “The discovery of nature is recorded not only in the words

  1 Third Earl of Rosse, On the Construction of Specula of Six-feet Aperture, and a selection from the Observations of Nebulae made with them, Philosophical Transactions of the Royal Society of London, 1861, p. 681.

  2 O. W. Nasim, Observing by Hand: Sketching the Nebulae in the Nineteenth Century, Chicago: University of Chicago Press, 2013, p. 36.

  3 W. L. Fox, in Alan Bean Painting Apollo, Washington: Smithsonian Books, 2007, p. 19.

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  of the explorers, it is also kept before us through the illustrations accompanying the history

  of this research, and the pictures make it much clearer to our sense than words could ever

  do.”4 This is what Alan Bean tries to convey to us about the nature of the lunar surface.

  Artists of Nature

  In previous centuries, it was common for scientists, naturalists in particular, to be proficient

  in drawing. A fine example was British geologist Charles Lyell (1797–1875), as shown

  by the drawings accompanying his influential Principles of Geology, published in three

  volumes in 1830–33.5 A remarkable counterexample was the great Swedish botanist Carl

  Linnaeus (1707–1778) who wished “to express by words all marks [of a plant genera] just

  as clearly – if not more clearly – as others with their splendid drawings.”6 Several scholars

  described Linnaeus as a poor draughtsman. Wilfrid Blunt wrote “Matisse once said that

  his ambition was to draw like his little girl of five; Linnaeus achieved this effortlessly.”7

  Isabelle Charmentier has given a balanced perspective of Linnaeus’s abilities with respect to

  the role and importance of drawing in botany that can be extended to other natural sciences.

  If Linnaeus was a reluctant draftsman, the discipline of botany has been a rich field for

  legions of artists. Belgian painter and botanist Joseph Redoute (1759–1840) was one of the

  most remarkable and productive of them, with a total of 486 plates for Les Liliacées, a plant

  particularly hard to preserve in any other way than through botanical illustration.8

  More established savants had official assistants to accompany them in the field and to

  execute sketching work under careful instructions. This practice was widespread in botany

  but also in other natural sciences.9 Along with young naturalist Charles Darwin, the Beagle

  survey expedition of 1831–1836 had on board artist and draftsman Conrad Martens (1801–

  1878) followed by Augustus Earle (c. 1793–1838). In the summer of 1838, Swiss biologist

  and geologist Louis Agassiz (1807–1873) took with him six collaborators, including an

  artist, to explore the glaciers of the Alps; this expedition led to several finely illustrated

  books and articles. English painter William Hodges (1744–1797) made sublime sketches

  and paintings of the various locations of the Pacific visited by James Cook during the second

  voyage. These were adapted and used as engravings in the original publication of Cook’s

  journal.

  Atlases and field guides of birds have been important ornithological works, providing

  information on species, their distribution and abundances. These works made extensive use

  4 A. Bettex, The Discovery of Nature, New York: Simon and Schuster, 1965, p. 372.

  5 C. Lyell, Principles of Geology, New York: D. Appleton and Company, 1872, 2 volumes.

  6 Cited in S. Müller-Wille and K. Reeds, A Translation of Carl Linnaeus’s Introduction to Genera Plantorum, Studies in History and Philosophy of Science, Part C: Studies in History and Philosophy of Biological and Biomedical Sciences, 2007, Vol. 38, No. 3, p. 568.

  7 Cited in I. Charmantier, Carl Linnaeus and the Visual Representation of Nature, Historical Studies in the Natural Sciences, 2011, Vol. 41, No. 4, p. 367.

  8 C. Fisher, The Golden Age of Flowers: Botanical Illustration in the Age of Discovery 1600–1800, London: The British Library, 2011, p. 21.

  9 I. Charmantier, Carl Linnaeus and the Visual Representation of Nature, Historical Studies in the Natural Sciences, 2011, Vol.

  41, No. 4, p. 394.

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  Part I – Images and the Cosmos

  of maps and especially of drawings, sometimes accompanied by spectacular colour plates,

  such works expressing a true art of ornithology.10 French-born American ornithologist and

  naturalist John James Audubon (1785–1851) was an outstanding painter of birds and of their

  natural habitats. The seminal Guide to the Birds by Roger Peterson (1908–1996) published

  in 1934 presented hundreds of drawings of birds of superb quality. This was the first of

  the Peterson field guides that assisted the interested layperson in identifying birds, insects,

  plants and other natural phenomena. The books used plates of drawings rather than pho-

  tographs of the subjects as an effective tool to highlight key markers. Atlases of birds full of

  faithful drawings and paintings are among the most magnificent books of natural history.

  English ornithologist John Gould (1804–1881) produced superb monographs of several

  species of birds.11 For example, A Monograph of the Trochilidae, or Family of Humming-

  Birds, had 418 stupendous hand-coloured plates.12 Charles Darwin referred to John Gould’s

  work in his On the Origin of Species.

  An interesting aspect of display in botanical and ornithological atlases was to show

  indigenous plants or flowers and particular insects with the birds darting or hovering near

  them. A fine example is The Book of Palms by German botanist and explorer Carl Friedrich

  Philipp von Martius (1794–1868).13 The massive Historia naturalis palmarum,with more

  than 240 chromolitographs, contained drawings of hundreds of palm families found in

  the various continents. Vivid scenic depictions are regularly interspersed amid the mag-

  nificent plates of multiple families and sub-families of palms. “Composite fictions” are

  another important dimension of scientific illustration, where visual information presents all

  life cycles and transformations. This is nicely shown in The Butterflies of North America,

  Titian Peale’s Lost Manuscript, where the caterpillar and pupa are shown sharing the stem

  of their food plant with the butterfly, male and female, displaying their upper and under

  surfaces.14 “In today’s world of image databases and laser printer, it can be hard to grasp

  the dedicated labor it took to craft one of these paintings, let alone thousands. A single

  image involved a close collaboration among plant collectors, botanists, and entire teams

  of artists who specialized in the various steps it took to achieve a finished illustration.”15

  Not only did the whole process involve several people, sometimes of multiple expertise,

  it required weeks or months of patient work and, very likely, much negotiation. Nature

  artists were particularly adept at presenting reconstructed scenes of ancient geological

  times (Fig. 2.1).

  As for botany and ornithology, the field of anatomy has been a discipline where s
ketch-

  ing and drawing have been and continue to be in constant use and development. Anatomical

  10 J. Elphick, Birds, The Art of Ornithology, New York: Rizzoli International Publications, Inc., 2015.

  11 J. Elphick, Birds, The Art of Ornithology, New York: Rizzoli International Publications, Inc., 2015, pp. 226–239.

  12 J. Gould, A Monograph of the Trochilidae, or Family of Humming-Birds, London: Henry Sotheran & Co., 1880.

  13 C. F. P. von Martius, Der Buch der Palmen, Cologne: Taschen GmbH, 2016. The three-volume Historia naturalis palmarum was published by T. O. Weigel of Leipzig between 1823 and 1850. The whole work weighed 28 kg with book-block dimensions of 60 × 43 cm.

  14 K. Haltman (introduction of), The Butterflies of North America, Titian Peale’s Lost Manuscript, New York: American Museum of Natural History/Abrams, 2015.

  15 D. Bleichmar, The Geography of Observation: Distance and Visibility in Eighteenth-Century Botanical Travel, in Histories of Scientific Observation, L. Daston and E. Lunbeck (editors), Histories, Chicago: University of Chicago Press, 2011, pp. 383–395.

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  Fig. 2.1 Etching from Myers Lexikon depicting the flora of the Carboniferous in Book 15, 1885.

  Credit: Bibliographisches Institut.

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  Part I – Images and the Cosmos

  drawings, however, do not necessarily aim for exact reproduction. Sometimes an idealized

  representation is sought, which can better fulfil a pedagogical purpose.16 In anatomy, this

  idealization has been pushed to the extreme, with the use of separate representations for

  various functions of the human body: blood circulation, the brain and nervous system, the

  skeleton, the muscles, etc. Indeed, anatomical sketches exploit the fact that hand-drawn

  pictures are best at highlighting a particular organ or body part; a photograph does not

  show the function or organ as clearly, and might instead hide its functional role. Anatomi-

  cal representations are almost abstractions for the mind, while displaying separately body

  functions in ways that are most useful for the neophyte and the advanced learner. Atlases

  of anatomy are part of a system of visual displays and schematics for dissection classes,

 

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