An Image Interview with Frances Willmoth

John Flamsteed’s Atlas Coelestis (1729): plate 13 of 25

Can you tell us briefly about yourself and your background?

I am Dr Frances Willmoth. I have recently retired as Archivist at Jesus College, Cambridge, but retain an affiliation to the Department of History and Philosophy of Science, Cambridge. A large part of my academic life has been involved with the careers of John Flamsteed (1646-1719), the first Astronomer Royal, and his patron Sir Jonas Moore (1618-1679).

Which picture have you chosen, and what does it show?

I have chosen a plate from Flamsteed’s posthumously published Atlas Coelestis (1729). It shows the constellation Monoceros – that is, the Unicorn – with Canis Major and Canis Minor.

Why have you chosen this image?

I’ve chosen something from the star atlas because the struggle to get it published had such a profound influence on the course of the last decade and a half of the astronomer’s life. This particular plate seems to me especially characterful, and artistically satisfying. The drafting of the artwork is credited to the well-known painter Sir James Thornhill.

How does this image resonate with you in the context of your work or research?

The chequered history of Flamsteed’s publications reflects the huge difficulty of publishing anything involving such enormous costs and technical challenges. The astronomer started a search for external funding for the publishing of his observations, star catalogue and atlas in the summer of 1703, by talking to one of the royal physicians and to Dr Martin Lister (FRS). His campaign eventually led to his securing a grant from Prince George of Denmark (Queen Anne’s consort). The subsequent unhappy history is well known, as the committee set up to supervise the expenditure disagreed with Flamsteed over how the project should be approached. The first edition of the Historia Coelestis (1712) was largely produced without the astronomer’s oversight and he rejected it as “spurious”. An extended second edition was not completed until 1725, some years after his death, and the star atlas even later.

Do you know anything about the making process of the image? 

Once the star positions had been established, the drafting of images for the plates was begun by one of Flamsteed’s observatory assistants, Thomas Weston. But he suffered from ill health and moved on in 1706 (becoming a schoolmaster in Greenwich). The connection of the finished plates with Thornhill dates from much later on, as a letter written by former Observatory assistant Crosthwait on 19 November 1720 reveals: “As to drawing the images … the famous Sir James Thornhill has undertaken this part, purely out of gratitude for favours formerly received from Mr Flamsteed”. In the previous decade Thornhill had spent a long time in Greenwich producing a spectacular decorative scheme for the Painted Hall at the Royal Naval College. Flamsteed himself appears in one of those paintings, with an assistant and his most famous astronomical instrument, the mural arc.

                  We don’t know what sources Thornhill looked to when it came to drawing the images for the Atlas, though he undoubtedly already had a large stock of suitable models. We know more about the lengthy process of getting the plates engraved. This was funded by Mrs Flamsteed, and is described in a series of letters written by Crosthwait to Abraham Sharp (another former Observatory assistant, who prepared the northern and southern planispheres). In 1722 Crosthwait travelled to the Netherlands to see if he could get plates engraved there more cheaply than in London. Consequently four of them were engraved in Amsterdam (Aquarius, Gemini, Cetus and one other), though the quality of the work proved disappointing and the rest were produced in London; all were printed in London.

What significance does the image have for the historical understanding of the relationship between knowledge-making and image-making?

It shows up how inadequate it might be to simply describe such an image as a source of knowledge. At one level it was intended to have that role, accurately reflecting the positions of stars as laid down in Flamsteed’s star catalogue (1712 and 1725). But the Thornhill connection places the plates squarely in the domain of fine art, reflecting the fact that the volume was aimed at noblemen’s or gentlemen’s libraries, as much as a being a working tool for future astronomers.

Do you have any additional thoughts or comments on the image you would like to share?

One point that comes across clearly here is that (as is not uncommon in the history of science) an achievement notionally credited to a single person in fact relied on the substantial contributions made by a number of collaborators. Here one must credit not only Flamsteed himself, for having produced the data, but also: the persistence of his widow Margaret and his former assistant (and niece’s husband) James Hodgson, who appear as editors of the volumes; the assistance given gratis by two more former Observatory assistants, Sharp and Crosthwait; Weston and Thornhill; and several engravers and at least one printer.

*Frances Willmoth is also the author of the children’s book Astronomouse. Copies can be purchased in person at the Whipple Library in Cambridge.

Copying Hevelius’s lunar template

By Nydia Pineda De Avila

Hevelius, Figura Primaria Phasium Lunarium in Selenographia, 1665 © Royal Society
Fig. 1: Hevelius, Figura Primaria Phasium Lunarium in Selenographia, 1665 © Royal Society

The word selenographia, a Latinized Greek noun derived from Selene (the moon), and graphia (from the verb graphein, to scratch, draw, write, represent, describe) was coined in the seventeenth-century to refer to textual and visual lunar description made from telescopic observations. From the 1640s, the word designates a map of the features of the satellite. In the production of these images, astronomers and artists engaged in graphical experimentation for the efficient translation of fragmentary views (it was impossible to see an image of the full moon at once through a seventeenth-century lens) into a detailed representation of the entire lunar disc. A gallery of seventeenth-century selenographies can be found here.

This image (Fig. 1) is perhaps the most abstract selenography of its time. The lunar features are not inscribed within a circle representing the limits of the disc but are floating on the blank page. The moon is not intended to look naturalistic: there is no expression of volume or tone as in the phases engraved by Claude Mellan under the direction of Pierre Gassendi and Nicholas Fabri de Peiresc or in the full moon drawn and engraved by Jean Patigny under Jean-Dominique Cassini. Here the depressions and elevations of the surface are reduced to irregular shapes engraved with a single line. A rhomboid grid marks an imaginary centre of the disc that was intended to orientate the user of the telescope. This is not a moonscape but a two-dimensional representation of the topography of the moon. Johannes Hevelius published the image in his lunar treatise, the Selenographia sive lunae descriptio, published in Gdansk in 1646.

Hevelius explains the use of this image as an astronomical instrument © Royal Society
Fig. 2: Hevelius explains the use of this image as an astronomical instrument © Royal Society

Hevelius used this template to reconstruct more detailed maps of the full moon and the forty phases that illustrate the Selenographia. The template itself, called Figura Primaria Phasium et Lunationum (called Fig. T and its variant Tt) was inserted in chapter 44 of the book; and in many cases copies of the figures were bound at the end of the volume. Hevelius explained this picture as a synthesis of observations taken across a period of four years. He presented the image as an astronomical instrument that would serve the recording of lunar eclipses, the occultation of celestial bodies, and the calculation of terrestrial longitude. The astronomer could shade or mark lines over the image to show the progress of a lunar eclipse or the places of the conjunction of a planet. The author’s intention was for his map to be transferred on to copper plates so that it could be easily reproduced and used across the world. However, the template was perhaps not as helpful as Hevelius would have liked (Fig. 2).

Hevelius, Transit of Jupiter over the moon 30 September 1671, Royal Society LBO/5/2/1 © Royal Society
Fig. 3: Hevelius, Transit of Jupiter over the moon 30 September 1671, Royal Society LBO/5/2/1 © Royal Society

Though engraving and etching was increasingly valued and practiced by amateurs throughout the seventeenth century, the reproduction of Hevelius’s template would have required not only knowledge of the craft and access to a roller press (or, these lacking, to an engraver) but also a real motivation. My survey of copies of this image in the archives of the Royal Society indicates that astronomers did not use Hevelius’s recording aid. Thus far, evidence suggests that they preferred to record lunar phenomena in tables and text rather than through illustration.

Hevelius’s correspondence and the copies of his papers do not frequently convey the results of observations through a visualisation: the earliest example of a communication accompanied by a lunar template representing the transit of Jupiter over the moon in September 1671 is found within the series now called Letter Book Original that gathers a selection of copies of autograph letters indexed by Richard Waller in 1689 (Fig. 3). This template is much smaller than the one printed in the Selenographia. The image was most likely sent with the intention of being published, for it was printed in the Philosophical Transactions to illustrate Hevelius’s communication.

Pen and ink copy of Figura Primaria. Johann Philipp Wurzelbaur, Lunar Eclipse 25 March 1689, Cl.P 8i 44 © Royal Society
Fig. 6: Pen and ink copy of Figura Primaria. Johann Philipp Wurzelbaur, Lunar Eclipse 25 March 1689, Cl.P 8i 44 © Royal Society

In the volume holding Hevelius’s correspondence with Henry Oldenburg, only three observations, all pertaining to the later part of Hevelius’s life, are illustrated with this reduced version of the Figura Primaria: two lunar eclipses of 1676 and 1682, and an occultation of Jupiter of 1686. These are also appended to tables and texts. Arguably, Hevelius also sent these papers aiming for them to be published. It seems that he used these templates not as instruments but as visualisations to communicate observations effectively to an interested yet not specialised readership (Figs 4 & 5).

Etched copy of Figura Primaria. Georg Christopher Eimmart, Lunar Eclipse observed at Nuremberg 25 March 1689, Royal Society Cl.P. 8i/ 38 © Royal Society
Fig. 7: Etched copy of Figura Primaria. Georg Christopher Eimmart, Lunar Eclipse observed at Nuremberg 25 March 1689, Royal Society Cl.P. 8i/ 38 © Royal Society

Remarkably, the lunar template is also scarce in observations sent to the Royal Society by other astronomers. Etched or pen and ink copies of Hevelius’s Figura Primaria are found in recordings of lunar eclipses taken between 1689 and 1690, which were sent by astronomers of the observatory of Nuremberg, Georg Christoph Eimmart and his collaborator Johann Philipp Wurzelbaur (Fig. 6). Notably, these astronomers also represented lunar observations with Hevelius’s template in self-published pamphlets promoting their work in Nuremberg in 1685 and in the periodical the Acta Eruditorum of 1686. Eimmart was an astronomer as well as an accomplished engraver but the fact that he was capable of making copies of Hevelius’s template does not explain why he and his friend decided to convey their results in this way (Fig. 7). I would like to understand if Eimmart and Wurzelbaur adopted Hevelius’s graphics in order to promote their work at the observatory of Nuremberg within his scientific legacy.

This example helps me continue my reflection about the purpose of lunar maps in the seventeenth century. The case of Hevelius’s Figura Primaria adds to a number of instances in which the motivation for producing maps of the moon is not purely astronomical. Thus far, I think that although the process of making selenographies is related to the desire to test technology and to further understand the topography of the satellite through observation and drawing, the publication of these images obeys the desire to promote a scientific identity.

Nydia’s own version of Hevelius’s Fig. T in drypoint and chine collé
Nydia’s own version of Hevelius’s Fig. T in drypoint and chine collé