row of astrolabes

Biennial History of Astronomy Workshop - ND XIII July 5-9, 2017


Public Invited Talk (Wednesday)

“The Antikythera Mechanism and the Mechanical Universe” (talk poster)
Michael Edmunds, Cardiff University, Wales, UK
Abstract: The idea of a “mechanical universe” tends to be associated with sixteenth- and seventeenth-century pioneers like Copernicus, Kepler, Galileo, and Newton. Yet recent investigations based around the Antikythera Mechanism, an ancient Greek artefact from around 100 BC, reinforce a view that the “mechanical” conception has been around for a much longer time-indeed certainly as far back as the third century BC.

The discovery of the structure and functions of the Antikythera Mechanism—a complex device that contained well over thirty gearwheels—will be described and illustrated in detail. A strong claim will be made that knowledge of mechanical representations of the Universe was critical in the development of cosmology and philosophy. There is evidence that the technology persisted until its spectacular and rather sudden re-appearance in Western Europe around 1300 AD. From then it is not hard to chart a path to Kepler’s aim (expressed in a 1605 letter) to “show that the heavenly machine is not a kind of divine, live being, but a kind of clockwork.”

Special Presentation:

“Astronomical Mechanism in Greece, Rome, and the Modern World”
Michael Edmunds, Cardiff University, Wales, UK
Abstract: This talk will give the opportunity for conference participants to (i) learn about more details of the Antikythera Mechanism and the literature sources that give it a context 300 BCE–500 AD, (ii) discuss the purpose of the Mechanism and the difficulties of interpreting these ancient literature sources, and (iii) trace the subsequent development of mechanical astronomical and computational devices.

Panel Abstract

“Teaching about the Extraterrestrial Life Debate”
Organizer: Michael J. Crowe, University of Notre Dame
Abstract: none.

Panel Paper Abstracts

“Teaching Extraterrestrials at Notre Dame: The One-Semester Undergraduate Course”
Michael J. Crowe, University of Notre Dame
Abstract: The first half of the undergraduate course I’ve offered at Notre Dame is based on my The Extraterrestrial Life Debate, Antiquity to 1915: A Source Book (ND Press, 2008). The second half treats post-1915 developments, using various sources, especially books by Steven Dick and by Stephen Webb. The format is a debate, and most of the student writing takes the form of each student taking a side and defending it. The debates correspond to the 1700 situation, the 1900 situation, and the present.

“Teaching the Extraterrestrial Life Debate in an Interdisciplinary Context”
Peter Ramberg, Truman State University
Abstract: Since 2004, I have taught a course on the extraterrestrial life debate for Truman State University’s Junior Interdisciplinary Seminar program. Juniors must take one of these courses that are offered in a wide variety of topics. My goal is for students to write a position paper on the existence of extraterrestrials, drawing on history, philosophy, theology, astronomy, geology, chemistry and biology. There are five major components to the course: debates over plurality to 1800, the nineteenth century, Mars, origin of life and intelligence, and the modern debate. In my presentation, I will provide more information on readings and assignments, and give an overview of student responses and positions.

“Teaching the History of the Extraterrestrial Life Debate”
Robert Smith, University of Alberta
Abstract: I will discuss teaching a senior undergraduate course on the history of the extraterrestrial life debate. In this seminar, students are required to tackle not just issues around extraterrestrial life, but also to engage seriously with the notion that the extraterrestrial life debate has been a very complex cultural product. I will relate briefly too my experiences integrating the history of the extraterrestrial life debate into a broad 300-level survey on the history of astronomy and cosmology.

“From ‘Ancient Aliens’ to UFOs: Using fringe ideas to explore critical questions in the History and Philosophy of Science”
Sarah Jozina Reynolds, Indiana University-Bloomington
Abstract: This talk will discuss how to address and incorporate the more “out-there” portions of the history of thought about extraterrestrial life in a course that addresses key philosophical and historiographical issues within the study of science, such as the nature of scientific evidence, the role of the scientific community, the challenges of interpreting data, historical shifts in judgments of scientific legitimacy, and how scientific authority can be leveraged for a variety of purposes, even well beyond the boundaries of science.

“Newberry Library Seminars on the Extraterrestrial Life Debate”
Lee Minnerly, Independent Scholar
Abstract: This presentation describes my experience teaching various topics in the debate at the Newberry Library in Chicago, an independent research library with collections focused on the humanities. The library is open to scholars and the public without charge and serves thousands of readers and researchers annually. My classes thus far have ranged from three to six sessions and include “When Mars Was Dying: Chicago and the Martian Canal Controversy” and “Early Science Fiction and the Extraterrestrial Life Debate.” I will discuss the format, contents, and outcomes for these and other classes.

“Teaching the Extraterrestrial Life Debate in Shorter Format”
Matthew F. Dowd, University of Notre Dame Press
Abstract: I have taught and co-taught courses about the historical debate over the existence of extraterrestrial life as both full semester courses and as portions of semester-long courses focused on the history of scientific ideas. In this presentation, I will discuss some of the challenges of teaching the shorter form, including choosing what topics to cover and what to ignore, the extent of the history to be taught, and whether or not to present the current state of affairs regarding the debate in a course that otherwise does not cover present-day science.

Panel Abstract

“Mechanism and Accuracy in Ancient and Medieval Astronomy”
Chair: Michael Edmunds, Cardiff University, Wales, UK
Abstract: Did physical mechanisms or devices really play a significant role in ancient astronomy? How did physical visualization compare with mathematical or other “explanations”? Did mechanism drive theory or theory drive mechanism? In the evolution of theories and the development of mechanisms, how important was “accuracy” either in reproducing observations or in being a criterion for “good/convenient/realistic” representation of the physical world? This session will look at these and related problems, and (time permitting) ask how the nature of mechanistic explanation has changed throughout the history of astronomy.

Panel Paper Abstracts

“From Babylonian records to pin and slot: A possible path” (paper)
Christián C. Carman, Universidad Nacional de Quilmes
Abstract: The Antikythera Mechanism is a mechanical astronomical instrument that was discovered in an ancient shipwreck at the beginning of the twentieth century, made about the second century B.C. It had several pointers showing the positions of the moon and sun in the zodiac, the approximate date according to a lunisolar calendar, several subsidiary dials showing calendrical phenomena, and also predictions of eclipses. Scholars agree that probably it also showed the position of the planets in the zodiac. In 2012 Carman and Evans on one side, and Freeth and Jones on the other, independently published a very similar proposal for the planets based on the pin and slot device, already deciphered for the Moon by Freeth et al. in 2008. One year later, Evans and Carman suggested that the epicycle and deferent system could have been originated using the pin and slot as an inspiration and not the other way around. According to that proposal, pin and slot devices were conceived as a mechanical solution for producing anomalistic motions in geared mechanisms and then, looking at it, some geometer proposed the epicycle and deferent system. But we did not propose any particular way in which the pin and slot model could have been designed departing just from astronomical data, without having in mind the epicycle and deferent model. In this talk I will propose a possible path that could have been followed by the designer of the mechanism.

“Mental Models, Mathematical Devices, and Physical Principles in Fifteenth-Century Islamic Astronomy: The Case of Fathallah al-Shirwani”
Scott Trigg, University of Notre Dame
Abstract: The astronomical observatory and school established by Sultan Ulugh Beg at Samarqand was the leading Islamic scientific institution of the fifteenth century, staffed with some of the most prominent scholars of the age. Samarqand, with its massive meridian arc and other instruments, is famous as a center for observational astronomy and the site where extensive observations of the fixed stars and planets were used to generate revised tables of astronomical data. However, the Samarqand astronomers were not solely concerned with mathematical calculations and practical astronomy. Drawing on the work of Fathallah al-Shirwani, a Samarqand astronomer who was later associated with the Ottoman sultan Mehmed II, this paper highlights the extent to which theoretical questions and critiques occupied a central role in the fifteenth century Islamic astronomical enterprise. Shirwani’s extensive commentary on Nasir al-Din al-Tusi’s al-Tadhkira fi ʿilm al-hayʾa contains numerous discussions illustrating how mental models, thought experiments, and principles from natural philosophy combined with observational evidence to understand the cosmos. These discussions reflect Shirwani’s critical engagement with existing astronomical texts and commentaries, and are enriched by his reports of analysis and debate in the Samarqand lecture hall.

“Explanation and Unification: A Closer Look at Aristotle’s Astronomical Model”
Shannon Abelson, Indiana University-Bloomington
Abstract: In Metaphysics XII.8 Aristotle provides a model of planetary motion, building on the work previously done by Eudoxus and Callippus, which posits celestial spheres to account for the movement of planets. Aristotle’s astronomical model introduces an important causal mechanism to explain the nature of planetary movement by positing “unwinding spheres” to attach to the extent spheres present in the model, unifying the disparate spheres of each planet into one system and preventing the compounding of their cumulative motions when they are joined. In this way Aristotle is able to both save and explain the phenomena. All spheres are kinetically motivated by the so-called “unmoved movers,” metaphysical principles serving as uncaused causes for physical phenomena. The positing of the unwinding spheres and their associated movers in Aristotle’s celestial model constitutes a very early example of an explanatory, mechanistic model in astronomy. Moreover, his emphasis on the ability of this model to explanatorily unify his astronomical system shows the importance this model played for his overall account of the universe.

“Methods and Models for Accurate Measuring”
Paul Keyser, Independent scholar
Abstract: Greek historians, philosophers, scientists, and technologists valorized accuracy (κρίβεια), from the fifth century BCE onward. Accuracy was required for describing the cosmos (Plato), for success in organizing escapes from circumvallation (Thucydides), for reliably releasing the racing horses (Kleiotas), and for correctly predicting the future phases of the solar year (Meton). Sometimes devices were constructed to assist in attaining accuracy, and such constructions usually depended upon a foundational model that advertised accuracy, often a geometrical or optical model.

Moreover, many of these attempts at accuracy, founded upon some particular model, were undertaken to support another more ambitious model. Dikaiarkhos used a foundational method that was optical, involving a dioptra, to support the cosmic model that the earth was very nearly a sphere, by measuring the heights of mountains. The later surveyor of mountain heights, Xenagoras son of Eumelos, claimed an accuracy (and precision) of one foot in six thousand and ninety-six. Archimedes as well deployed a dioptra, separately established the accuracy of the balance, and also invented an accurate method of determining what we call specific gravity—though it is not always clear what was Archimedes’ overarching goal. Ktesibios designed a mechanism of water and gears for accurately monitoring the regular progress of time. Ptolemy designed, apparently ab initio, a water-tank for measuring the angle of refraction, and performed his measurements so accurately that modern analysts can show that they closely fit the law of refraction, as enunciated by Ibn Sahl in 984 and Snell in 1621.

The dioptra was used from the time of Hipparkhos (or earlier) to observe stars and walls, accurately, and Heron describes a much improved, or at least more complex, version of the instrument. Ptolemy records two devices for observing the equinox, the meridional ring and the simpler graduated quadrant. He also designed two devices for measuring the positions of stars with great accuracy, the parallactic instrument (“Ptolemy’s rulers”) and the armillary astrolabe. In all of these astronomical cases, it seems that the goal was to acquire data sufficiently accurate to support a reliable model of the sun, moon, and even planets, in order to supply accurate predictions. As late as the fifth century CE, philosophers such as Ammonios were still occupied with measuring accurately the conjunctions of planets and stars, perhaps to contribute to the debate about the structure and size of the cosmos.

Panel Abstract

“Pathways and Footwear for the Next Generation”
Chair: Rudi Paul Lindner, University of Michigan
Abstract: The goal of this session is to bring together a few members of different generations in the field, allow them to express their own ideas about intriguing problems and productive methods, and then give the audience time to comment and point out possibilities appealing to them as well. The guiding assumption behind this is that while we all have our own rows to hoe, we also have much to teach and to learn, and from such a discussion there may arise a happy inspiration or a discovery, a bright nugget to search out, or a new instrument of research that will improve not only our own harvest but lead to a more variegated and promising garden.

Each of the panelists represents a different career path in the field, with rather different experiences, and each will offer an outlook on future prospects and approaches that will reflect his or her individual perspective. At the conclusion of the relatively short presentations, the audience is invited to address the issues and bring up new ones.


- David DeVorkin, National Air and Space Museum, Smithsonian
- Thomas Hockey, University of Northern Iowa
- Teasel Muir-Harmony, National Air and Space Museum, Smithsonian
- Marc Rothenberg, National Science Foundation (retired)

Adler Sessions Paper Abstracts

“Astronomical Volvelles in Chicago: Early Paper Engineering from the Sublime to the Ridiculous”
Suzanne Karr Schmidt, Newberry Library
Abstract: This case study will discuss the production process of several important early modern books with astronomical volvelles using exemplars in Chicago collections. For the fifteenth century, the Ratdolt edition of Regiomontanus’s Calendar (1576) at the Art Institute of Chicago offers an outstanding example of user interaction and close copying of the much-plagiarized original. The Adler Planetarium’s Astronomicum Caesareum (1540) marks Peter Apian’s most work-intensive publication, which involved his entire family workshop for several years, and eventually gained him a noble title. Finally, the Newberry’s copy of Robert Dudley’s Arcano del Mare (1645–46) will be analyzed in terms of the construction of its many dials. New evidence will be brought to bear on the publication of the book, including a newly discovered letter written by Dudley (also at the Newberry).

“Early Telescopes: Archives, Images, And Objects”
Marvin Bolt, Corning Museum of Glass
Abstract: A decade ago, Paolo Molaro and Pierluigi Selvelli described depictions of telescopes in several paintings by Jan Breughel the Elder between 1608 and 1625, suggesting that they provided evidence of Keplerian telescopes. The absence of any extant Keplerian instruments made it difficult to assess their claims. Over the past decade, we have located and identified over 1000 refracting telescopes made before 1750. Our recent discovery (2015) and subsequent investigation of two surviving early Keplerian telescopes (located in Kassel and Jena, Germany, with a potential third example in Beijing) provides material evidence contrary to the Keplerian claim by Molaro and Selvelli. In addition to articulating the specifics of this case, we address the larger issue of how we might interpret archival, representational, and material sources for conducting research on the history of astronomy, and illustrate these points with a look at the oldest telescope in the Adler’s collection, M-421, which we can date to ca. 1644.

“George Graham and the Orrery”
Rory McEvoy, Royal Observatory, National Maritime Museum, Greenwich
Abstract: In his 1734 discourse on the planetarium, John Theophilus Desagulier was careful to point out that the invention of the orrery had been incorrectly attributed to John Rowley and that it was George Graham who had made the first truthful working model of the Earth and moon’s motion around the Sun. Two such models by Graham survive in museum collections: one at the Adler Planetarium in Chicago and the other at the Museum of the History of Science in Oxford, UK. This paper will assess the differences between the two instruments and the physical evidence contained within to test out the assertion made by Henry C. King that the Adler instrument is the prototype and the Oxford orrery a developed commercial product. Through these orreries and contemporary accounts, this paper will introduce George Graham as an astronomer and instrument maker as well as evaluate how his astronomical model may have influenced contemporaries in the London trade.

“Francesco Bianchini (1662–1729) and the Origins of Planetary Globes”
Luís Tirapicos and Thomas Horst, Centro Interuniversitário de História das Ciências e da Tecnologia - Universidade de Lisboa
Abstract: The Veronese astronomer and antiquarian Francesco Bianchini (1662–1729) was a prominent figure in the papal court, occupying the positions of a chamberlain of honor, secretary to the commission on the calendar, and president of the antiquities of Rome in the pontificates of Clement XI (p. 1700–1721), Innocent XIII (p. 1721–1724), and Benedict XIII (p. 1724–1730). In his influential treatise Hesperi et Phosphori nova phaenomena sive Observationes circa planetam Veneris, published in Rome in 1728, he presents the first cartographical depiction of the planet Venus, containing the gores for a globe. Altogether, at least four Venusian globes were produced in Italy, whereof two still exist as originals in Paris (BnF) and Bologna (Museo della Specola). In this presentation, the surviving globes will be analyzed in detail and compared with two additional copies, which show the development and reception of Bianchini’s unique cartographic picture of the planet: a metal globe was sent to Lisbon to his patron, the Portuguese King João V (1689–1750), in 1728, and is depicted in the frontispiece of his treatise. Another copy was offered to the Royal Society in London. With these so far unknown Venusian globes, Bianchini gives us the first known three-dimensional model of a planet (if we exclude earlier examples of the earth and the moon).

“Recounting the Orbs: Visual and Material Cultures of Popular Astronomy and the Evolving Image of the Solar System, 1780–1860”
Pedro M. P. Raposo, Adler Planetarium
Abstract: The picture of the solar system changed significantly between the 1780s and the mid-nineteenth century, with the addition of Uranus, Neptune, the first asteroids, and several satellites. The nomenclature and classification of these objects and the debates they triggered among the astronomical community have been extensively researched. A related subject that still requires further attention is how this evolving picture of the solar system was presented to and received by wider audiences, especially taking into account that market niches for didactic instruments and popular publications had a significant growth during this period. How were these newly found orbs incorporated and presented into models and diagrams intended for non-expert audiences? What challenges and opportunities did they represent to authors and publishers of popular books and prints, and to makers of scientific instruments and toys? How important were these materials in shaping the image of the solar system? And more generally, what can we learn from their study with regard to the idea of discovery in the teaching and popularization of astronomy? I will address these questions by analyzing some examples of planetaria, Copernican armillary spheres, and solar system diagrams in the collections of the Adler Planetarium.

“Lunar Crater Models: Sharing Knowledge, Devising Theories, and Creating Photographic Aids”
Louise Devoy, Royal Observatory, Greenwich
Abstract: With its numerous photographic plates, the publication of The Moon: Considered as a Planet, a World, and a Satellite by James Nasmyth (1808–1890) and James Carpenter (1840–1899) in 1874 clearly demonstrated the aesthetic and pedagogical value of creating lunar crater models. The narrative of how the authors translated their telescopic observations into plaster models to be used as photographic aids is well known, but in this paper I will re-examine their work within the context of other extant models. For example, the Science Museum, Royal Astronomical Society, and Whipple Museum have models created by the English chemist Henry Blunt (1806–1853) during the 1850s, over twenty years before Nasmyth and Carpenter’s book. Similarly, two models made by the Spanish astronomer and sculptor Dionis Renart (1878–1946) around 1910, now held at the National Maritime Museum, demonstrate how interest in creating lunar crater models continued into the early twentieth century. By comparing these surviving models we can assess the rationale behind their construction and explore the networks of knowledge and expertise among lunar cartographers during the late nineteenth century.

Adler Play

“Sir Isaac Remembers....”
A One-Man Play by Michael Edmunds
Description: Sir Isaac Newton is sorting out his letters during the last year of his life. This dramatic reconstruction, lasting about one hour, is based entirely on authentic letters, contemporary reports and material. Sir Isaac offers thoughts on his science, his life, his lesser-known studies in alchemy and religion, and the world in general.

Individual Paper Abstracts

Durruty Jesús de Alba Martínez, Universidad de Guadalajara
“On Comets and Knowledge: From Astrology to Astronomy”
Abstract: For a long time, comets appearing in the sky were associated with bad omens and were understood as bearers of misfortunes. This paper includes a review of rare books that address the issue from different libraries in New Spain, from a quite curious edition of Manilius’s Astronomicon (Paris, 1679), passing by Henrrico Martinez’s Reportorio de los tiempos (México, 1606), to the titles that perform the first modern academic discussion concerning their nature that were published in Mexico City on the occasion of the great comet of 1680–81, namely, those by Eusebio Francisco Kino, S.J., and Carlos de Sigüenza y Góngora, showing the transition from astrology to astronomy.

Trudy E. Bell, Independent Scholar
“The First (Brooklyn) American Astronomical Society”
Abstract: Sixteen years before the founding of today’s American Astronomical Society, another group with that same name was founded in 1883 in Brooklyn, New York, by wealthy amateur astronomers, academics, active observers, and telescope makers. Five years later, the Brooklyn AAS apparently disappeared. Nonetheless, the group had become well-known enough that professional astronomers forming their own organization in 1899 initially chose the name of the Astronomical and Astrophysical Society of America in part to avoid potential confusion, and did not adopt its present name of the AAS until 1914. Eventually, knowledge about the history of the first Brooklyn AAS faded into obscurity.

Two unpublished scrapbooks—one in a New York library and the other privately owned—document that the Brooklyn AAS did not disappear but became the astronomy department of the newly reorganized Brooklyn Institute of Arts and Sciences (today the Brooklyn Museum). Meeting transcripts, newspaper clippings, correspondence, minutes, and membership lists from 1883 through 1948 chronicle how monthly speakers included eminent astronomers who addressed audiences often ranging from 200 to 1,200 auditors. Members’ private observatories and telescopes included a 12-inch refractor, then one of the largest telescopes in private hands (acquired by Wellesley College to become the main instrument for the Whitin Observatory in 1900). The group’s speakers, officers, and executive committee included notables who subsequently became charter members of the professionals’ AASA/AAS: George Ellery Hale, Antonia C. Maury, Henry M. Parkhurst, Garrett P. Serviss, and Charles A. Young. And the group’s membership appeared to be up to a quarter women—a high percentage even for astronomical societies today-some of whom held office and served on the executive committee; women also numbered among invited speakers.

Jake Bridges, University of Alberta
“A Science Fit for the Chapel: Astronomy, Communities of Science, and the Nature of Knowledge in Wales, 1805–1914”
Abstract: This paper analyzes astronomy and the dissemination of astronomical knowledge in Wales during the nineteenth century. I argue that the social and cultural contexts in Wales influenced how astronomy was practiced and published, and I compare developments in Wales to those in Ireland and Scotland. A study of Welsh perceptions of astronomy helps to understand what British astronomy meant to both astronomers and the public in the nineteenth century, and I examine how astronomy was used differently to conform to Welsh preconceptions of nature and the universe. Scientific interests in Wales have been dismissed by previous scholars for a number of reasons, including the Bible-centric nature of Welsh society and difficulties of incorporating scientific terminology into the Welsh language. I refute these dismissals, and instead argue that astronomy played a significant role within Welsh society, as evidenced by the popularity of astronomical lectures, scientific journals and societies, and culturally prominent amateur astronomers. This paper begins with the first Welsh scientific periodical published in 1805 and ends with the disbandment of the Astronomical Society of Wales in 1914.

James Caplan, Université d’Aix-Marseille, France
“The Occulting Alidade”
Abstract: The planetary positions determined by Tycho Brahe at the end of the sixteenth century were of astounding accuracy-an order of magnitude better than those previously available. This accuracy, around a minute of arc, allowed Johannes Kepler to establish some years later that the orbit of Mars was an ellipse. What made this accuracy possible? The telescope had not yet been invented. Did Tycho possess extraordinary eyesight, as has often been asserted? Part of the answer certainly lies in Tycho’s careful reduction calculations and his understanding of observational uncertainties. But the main reason is that, contrary to what has generally been assumed, Tycho’s instruments were not limited by the resolution of the observer’s eye. They incorporated sighting systems I call “occulting alidades,” involving not the usual pinnules, but knife edges. The eye served essentially as a light detector. As the Keplerian telescope with crosshairs began to be used later in the seventeenth century, the occulting astrolabe was abandoned, except by Johannes Hevelius, in Gdańsk, who was strongly criticized, notably by Robert Hooke. The optical principle could have been explained in the seventeenth century by simple geometrical optics, but was not. We now can see that it is limited by diffraction.

Jamie Day, Transylvania University
“The History and Conservation of the Barlow Planetarium”
Abstract: In the mid-1800s, Thomas Harris Barlow-an agricultural industrialist and mechanical savant-designed an intricate and expansive mechanical model of the inner solar system. Barlow collaborated with James Dodd-mathematician and president of Transylvania University-to calculate the gearing, and labored for over a decade before arriving at his final design: a thirteen-foot diameter mechanism of wood, glass, filigreed cast iron, and precision gears. For nearly fifty years Barlow and his son, Milton, manufactured and marketed the planetarium, which was met with great acclaim. Unfortunately, the enormous stresses inherent in such a large instrument frequently led to mechanical failure. Recently, two examples have been beautiful conserved and returned to exhibit, and restoration of a third planetarium is underway. This talk will review the history of Barlow’s planetarium and the current state of the models that survive.

Corey Dethier, University of Notre Dame
“Single-Body Idealizations in Newtonian Mechanics”
Abstract: I identify and describe “single-body idealizations,” a type of idealized model whose use is ubiquitous in Newtonian physics and astronomy. Single-body idealizations are identified by three conditions: (1) a focus on (the motion of) a single body relative to the rest of the system, (2) a relaxing of the third law, i.e., the model need not include a force equal and opposite to every postulated one, and (3) an assignment of forces whose sole criterion of adequacy is that their sum is related to the observed total acceleration of the body by the second law. Despite the wide usage of these models, single-body idealizations are not representative of modeling practice in Newtonian astronomy more broadly. In particular, Newtonian astronomers interested in identifying the mechanisms behind the motions of planets imposed additional constraints on their modeling practice to narrow down the class of admissible models. I end by briefly drawing some conclusions about the different uses of models in Newtonian astronomy and mechanics.

Jacqueline Feke, University of Waterloo
“Image Making in Ptolemy’s Astronomy and Geography”
Abstract: Astronomy and geography are complementary sciences for Ptolemy. In fact, several chapters of Book 2 of the Almagest examine geography, including the list and description in Chapter 6 of the Earth’s parallels. In this paper, I will examine the use of images, and the relation of text to image, in Ptolemy’s astronomical texts, including the Almagest, Planisphere, and Planetary Hypotheses. I will argue that these images serve a number of functions-including mathematical demonstrative, exhibitory, and assistive to memory-and yet the role of images in astronomy differs from the function of maps in geography because of the respective goals and proper styles of exhibition of these sciences.

Christopher Graney, Jefferson Community & Technical College
“Science Drops the Ball—The Mechanics of Free-fall on a Rotating Earth as Anti-Copernican Argument”
Abstract: If the Earth rotates, then how should a falling heavy body behave? This topic was of interest to anti-Copernican writers, who argued that the vertical motion of a freely falling heavy body argued in favor of an immobile Earth. This paper will give a brief overview of several anti-Copernican writers, including Brahe, Locher, Riccioli, and Dechales (late sixteenth to late seventeenth centuries), who addressed the mechanics of a falling body on a rotating world. Some of these writers clearly envisioned and illustrated the “Coriolis Effect” now known to be present in any rotating frame of reference.

Gustav Holmberg, University of Gothenburg, Sweden
“Time Balls, Telegraphy, Radio Signals, and Public Clocks: Astronomy and the Distribution of Synchronized High-Precision Time in Sweden, 1850–1920”
Abstract: This paper studies the production and distribution of accurate time in Sweden, a field where astronomy had substantial practical applications. Time-related astronomical expertise, instruments, and techniques aligned with commercial interests, navigation, and, more generally, the overall synchronization of daily life in the modern city. Precise time had both a practical and cultural value in the late nineteenth century; it was produced at central standard institutions such as astronomical observatories and state-run navigational schools, and was distributed through a network of telegraph wires, publically visible clocks, and time balls.

Johan Kärnfelt, University of Gothenburg, Sweden
“The Three-Handed Clock and the Standardization of Time in Sweden”
Abstract: In 1862, with the inauguration of the national railway between Sweden’s two main cities, Stockholm on the east coast and Gothenburg on the west coast, Swedes had to get used to a new device, the three-handed clock. Up until then telling time had been a quite straightforward task; you made a stop at a watchmaker’s shop and adjusted your watch in accordance with the local mean solar time made available by the watch master. But since it was impractical, even impossible, to manage railway time tables on local solar time-it differs 24 minutes between the two cities-railway officials had decided to use the local mean solar time for Gothenburg’s meridian as official railway time in Sweden. Thus, and up until the introduction of a national standard time in 1879, Swedes that needed to travel had to keep in mind the difference between the local time on their watches, and the time used on the railways. To help administer this all clocks on station buildings had two minute handles, one telling local time, and one railway time.

Starting with the three-handed clock my presentation will focus on the process leading up to the 1879 reform, especially the role played by the astronomical expertise at the Royal Swedish Academy of Sciences. Throughout the nineteenth century the Academy was an important consultative body for the government in all issues with bearing on scientific matters, and it was the Academy’s astronomers that drew up the plans for a Swedish standard time.

John M. LoSecco, University of Notre Dame
“History of the Observation of Neutrinos Produced by Supernova”
Abstract: On February 24, 1987, the astronomy and astrophysics community was blessed with the nearest supernova since 1604. This extra-galactic event in the Large Magellanic Cloud occurred in contemporary times where instrumentation to observe over a broad spectral region, including ultraviolet and gamma rays, could be deployed. It occurred in the modern period when photographic records permitted an understanding of the progenitor. Most fascinating was observations of neutrinos that permitted confirmation of the explosion mechanism. The time, energy, scattering angle, and perhaps flavor makeup of the neutrino burst were a major triumph for our understanding of late stages of stellar evolution at a time when the solar neutrino problem was a source of confusion. This paper will concentrate on the state of the field prior to 1987 when a handful of astrophysicists were willing to wonder, to model, and to hope that relatively new discoveries in weak nuclear interactions would play a major role in the stellar collapse, neutron star, and supernova mechanisms. Contributions of Eddington, Fowler, Chandrasekhar, Zwicky, Oppenheimer, Colgate, Wilson, and Bethe, as well as a few observers who took the ideas seriously, are considered. The rise of gauge theories and the discovery of the weak neutral current also helped lay the groundwork for this momentous discovery.

Andrew Oakes, University of Toronto
“Stellar Spectroscopy and John S. Plaskett’s Leadership within Early Twentieth-Century Astrophysics in Canada”
Abstract: From the perspective of the science of astronomy, the interpretation of the light spectrum was a fundamental development in the chemical analysis of celestial starlight. The breakthrough discovery with the application of spectroscopy in 1859 inaugurated a new period in astronomy that evolved into astrophysics. It launched a continuing episode of new astronomy that was later embraced in early twentieth-century Canada where it was spearheaded by Canadian physicist and scientist, John S. Plaskett (1865-1941). The research work of John Plaskett at the Dominion Observatory in Ottawa, Ontario, from 1903 and, later, the Dominion Astrophysical Observatory in Victoria, British Columbia, from 1918, brought international recognition to Canada’s early efforts in astrophysics. Plaskett led a small cadre of Canadian astronomers who worked under him on their astrophysical research programs. Historically, Plaskett found himself to be the right person, in the right place, at the right time, and with the right temperament during the episode spanning 1903 to 1935.

Steve Ruskin, Independent Scholar
“Big Money and Blind Faith: Astronomy as a Model for Scientific Instruction in Late-Nineteenth-Century Colorado”
Abstract: This talk will consider astronomy’s role in the founding of three institutions of higher learning in frontier Colorado in the late nineteenth century: the Colorado College, the University of Denver, and the short-lived Presbyterian College of the Southwest. All of these schools built observatories and obtained good telescopes. However, of the three, only two still exist, and only one still has a working observatory. I will consider how astronomy played an important role in the early development of these institutions; and how, over time, astronomy as a model for scientific instruction in higher education was seen as either too expensive or insufficiently popular (or both). As a result, the teaching of other sciences-laboratory sciences in particular-became more prominent.

Emily Simpson, Oregon State University
“Ant Races and the Origin of Life in the Universe: Harlow Shapley’s Model of Cosmic Evolution”
Abstract: In 1919–20, in his down time, astronomer Harlow Shapley (1885–1972) raced ants on the grounds of Mt. Wilson Observatory. Though this activity sounds a bit eccentric at first, perhaps a strange hobby, Shapley’s investigations into the evolutionary biology of ants would come to influence his later models of how life develops in the universe. Shapley studied two species of ant-the California Harvester Ant and Velvety Tree Ant, both species local to southern California. He took an interest in his surroundings and made use of local fauna in his studies. As evidenced in his manuscripts and correspondence, Shapley took his ant project very seriously and even wrote up his findings for publication. He corresponded with entomology departments at UC Berkeley, Harvard, and the University of Chicago, as well as the New York Zoological Society and the Smithsonian. His work was largely dismissed as echoing existing studies, but his dedication shows that Shapley was very keen to participate in the field of evolutionary biology and conceived of himself as an interdisciplinary scientist. My doctoral dissertation, in part, argues for the role of interdisciplinary research at observatories in the Western U.S. from 1888-1928 and for the influence that such interdisciplinarity came to have not only on research programs but also on the thoughts and professional identities of the people involved. In this presentation, I will talk about an example I’ve taken from my research at Harvard University Archives and demonstrate that Shapley’s work in entomology had a significant influence on his later, more well-known work in cosmology.

Adriana Monica Solomon, University of Notre Dame
“The Equation of Time”
Abstract: The equation of time expresses a relation between the mean solar time and the true solar time (for a long time the latter was measured by using sundials). Its history intersects several disciplines: the history of astronomy and that of applied mathematics, of time-keeping technology, etc., and the works and writings of several astronomers and natural philosophers. Examples include Johannes Kepler, Christiaan Huygens, Jeremiah Horrocks, John Flamsteed, and Robert Hooke.

The equation of time is also mentioned in one of the most quoted passages from Newton’s Principia (1687). In the scholium to the definitions, Newton introduced a set of distinctions with respect to time: absolute, true, and mathematical time was to be distinguished from the relative, apparent, and common time. In the same paragraph, Newton also mentions the equation of time. Very often in the history of philosophy of time, the latter part is usually omitted (as is the reference to the satellites of Jupiter) and the distinction is considered to pertain to the metaphysical foundations of his project.

This paper develops the significance of the equation of time for both the history of astronomy and the philosophy of time. I begin with theoretical and practical aspects of the use of the equation of time provided by Hooke’s and Huygens’s works, and trace their influence on Newton’s distinction. I show that the connection between the types of motion and rules for their composition was achieved via a sophisticated geometrical apparatus in which time is an essential parameter. Thus I first argue that Newton’s distinction was in part motivated by the mathematization of motions connected to a more accurate equation of time. Secondly, I illustrate that the astronomical texts describing the equation of time following the Principia adopted Newton’s distinction. I conclude by developing the importance of future research at the intersection between the history of astronomy and the conceptual foundations of scientific theories.

Aníbal Szapiro, Universidad de Buenos Aires
“Ptolemy’s Proof of the Central Position of the Earth”
Abstract: In his Almagest [I, 5; Hei 1, 17], Ptolemy provides an astronomical proof that the Earth is at the center of the heavenly sphere. As is commonly pointed out, it is an indirect proof because any other possible position has consequences that are not compatible with astronomical observations. And, as it is generally underlined, it proves only that the Earth is relatively in the center of the heavens (what Copernicus uses in his De Revolutionibus [I, VI] to propose that it is not the Earth but the Sun that is in the center, while the Earth is relatively close). In this talk, I state that the success of Ptolemy’s proof depends on many assumptions that are not usually pointed out. Given the Ptolemaic meaning of some astronomical concepts used in the proof (such as horizon, equator, pole, ecliptic, or sphere), the experience shows that the Earth must be in the center of the heavenly sphere (or near). But, given other meanings (as those after Galileo), the experiences do not prove anything about the position of the Earth in the universe. So the meaning of concepts played a decisive role in the acceptance of the central position of the Earth.

Chaokang Tai, University of Amsterdam
“Anton Pannekoek and the Dutch School of Astrophysics”
Abstract: The Netherlands presents an interesting paradox in the history of early twentieth-century astronomy. In a period when large high-altitude observatories in dry climates became increasingly more important, multiple astronomers from this flat, low-lying, wet country rose to prominence. In my presentation, I will focus on the astronomical research of Anton Pannekoek, an astronomer without an observatory, who also happened to have been a prominent Marxist. I will explain how his socialist epistemology can help us better comprehend his unique methodology, which led to his early support of Shapley’s extended galaxy and his famous Milky Way drawings that ended up in the Zeiss planetariums. I will also go into how Pannekoek’s modeled stellar atmospheres and draw parallels with the general development of quantitative astrophysics. In particular, I want to explain how the limitations of his location influenced his research in this subject field.

Todd Timberlake, Berry College
“The Confusing Appearance of the Naked-Eye Planets”
Abstract: To the naked eye, all of the visible planets appear as tiny circular disks. For this reason, many ancient and medieval authors concluded that the planets were either self-luminous or that they were translucent and became completely infused with the light of the Sun. At the same time, Ptolemaic (or Copernican or Tychonic) planetary theory predicted that the distances of Venus and Mars should vary by a factor of about 7. Thus, the angular diameter of these planets should vary by the same factor and the areas of their disks should vary by about a factor of about 50. In fact, the apparent size of Venus hardly seems to vary at all. The apparent size of Mars does vary noticeably, but much less than was predicted by planetary theory. The two chief causes of these confusing appearances are now understood. The appearances of the naked eye planets are affected by phases (particularly for the inferior planets), but most importantly by limitations of human vision. Galileo’s telescope exceeded those limitations and revealed the phases. His observations helped to clear up the mysterious appearances of the planets, but led to a new mystery regarding the appearance of the fixed stars. I will present some of the technical details behind this fascinating episode in the history of astronomy.

Henry Zepeda, Bayerische Akademie der Wissenschaften
“The Recovery of Peurbach’s First Six Books on the Almagest
Abstract: The Epitome Almagesti, arguably the highpoint of the Ptolemaic tradition, is a summary of Ptolemy’s Almagest, which was the most authoritative work of astronomical theory for almost 1500 years. At the request of Cardinal Bessarion, Georg Peurbach began to write a better version of the Almagest than was currently available in Latin, the Epitome Almagesti. After his death in 1461, his younger colleague, Johannes Regiomontanus, completed the work of his former teacher. Regiomontanus reports that Peurbach had completed the first six books. These six books do not survive as Peurbach originally wrote them. Because we only have manuscripts that show the more or less finished version of the work after Regiomontanus had added seven more books and revised the portion written by Peurbach, it is difficult to determine how Peurbach’s six books originally appeared. In this talk, I discuss the process I am using to attempt to recover Peurbach’s work in its original form, working from codicological evidence, linguistic analysis, and comparison of the mathematical methods and styles of each author. I will then discuss the revisions that Regiomontanus made to these first six books and suggest some motivations for such changes.

Stefan Zieme, Humboldt-Universität zu Berlin
“Albrecht Dürer and the Melancholy of a Portentous Comet”
Abstract: For more than five centuries, an unbroken spell has accompanied Melencolia I, the most enigmatic engraving of Albrecht Dürer’s three Meisterstiche: What comprehensive message did Dürer encode in the proliferating iconography of his copper plate engraving from 1514? Despite countless attempts, no all-embracing interpretation integrating the multitude of single decoded details ever became accepted in art history. Variety and ambiguity crystalized to be the essential features of the engraving. The prominent celestial scene of a cometary apparition, present in the engraving, has been subjected to this reading, too. Yet, the comprehension of cometary apparitions in the Renaissance was a different one. Comets were distinguished celestial phenomena that heralded specific earthly implications, and their representations were symbolically rendered in an accessible iconography of the astronomical order. Dürer’s engraving complies to this model of cometary interpretation, albeit less obviously. It can be tied to a real and specific apparition of a comet in history and its dreadful earthly aftereffects. Melancholy emerges from the complete failure of astrological prophecy being at odds with earthly events-reason had failed to cope with catastrophic times.

This reading of Melencolia I from the viewpoint of the history of astronomy-as an allegory of a mental model of cometary lore and especially its failure-integrates all seemingly inconsistent details of the engraving, and offers what art history has despairingly been seeking for centuries: the missing piece of the puzzle that allows an all-embracing interpretation.

Poster Papers

“A 1-1/2-Inch-by-3-Inch Model of the Adler Planetarium”
Thomas Hockey, University of Northern Iowa
Abstract: Founded in 1912, The A. C. Rehberger company of Chicago (later A. C. R., Ltd.) was one of two American companies of the 1930s that specialized in hand-molded, hand-crafted, metal figurines, paperweights, desk sets, and bookends. During this decade it also made metal coin banks and miniature buildings produced as giveaway promotions. One of these buildings was the Art Deco Adler Planetarium.

Collectors consider Rehberger buildings of superior quality because of their attention to detail and quality casting. The Adler paperweight (note the felt backing), probably bronze, was designed by Eugene Sigle. It was made to coincide with the Chicago Century of Progress Exhibition, 1933-1934.

Provenance: The model on display was given to an Adler Planetarium volunteer in the 1950s. At his death, it went to his mother. She gave it to me as a gift.

Rehberger went on to make ash trays, desk plates, sports trophies—even the first Oscar set. In the 1970s, Rehberger was bought out. The Art Institute of Chicago acquired a set of Rehberger buildings, now called the “Miniature Building Collection 1920-2002.” It contains forty models, including an Adler Planetarium.

This Month in Astronomical History: Providing Context for the Advancement of Astronomy”
Teresa A. Wilson, Michigan Technological University
Abstract: This Month in Astronomical History is a short (~500 word) illustrated column hosted by the American Astronomical Society. Its mission is to highlight people and events that have shaped the development of astronomy to convey a historical context to current researchers, to provide a resource for education and public outreach programs seeking to incorporate a historical perspective, and to share the excitement of the field with the public. Knowing how the astronomical journey has proceeded thus far allows astronomers to map where to go next and plot how to get there. This Month in Astronomical History charts the former. While the column is by its nature event-driven, celebrating anniversaries of births, discoveries, and deaths, the significance of many of those events lies in how they reshaped the models in use or provided new mechanisms for research. Many of the featured people or events relied heavily on or made a significant improvement to existing models and mechanisms: Edwin Hubble shaped the model for the size of the universe, the discovery of Pluto changed the model for Solar System bodies, Sputnik was the first successful mechanism to orbit Earth. Therefore, the column shows the advancement of astronomy through a progression of its models and mechanisms Explaining the models and mechanisms of the past also conveys to the public the incremental and collaborative nature of each individual advance. While some early astronomers were both theorists and instrumentalists, many today work in highly specialized fields, relying on engineers to build the equipment they need to test the hypotheses proposed by theorists. The column puts these different pieces together and provides readers with a more complete history of astronomy. The Dudley Observatory is supporting This Month in Astronomical History through its 2017 Herbert C. Pollock Award.

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