|SINCE the Museum remains closed to visitors, it seems appropriate to feature a ‘guest sphere’ in this issue of Sphæra, one that can be viewed not far away in the building next-door, the Sheldonian Theatre.
In the balcony of the Sheldonian hangs a large portrait in oils of the Theatre’s architect, Christopher Wren. It is perhaps the best-known likeness of Wren: painted in about 1708, it shows him surrounded by evidence of his achievements in architecture and astronomy. It is signed as the work of no fewer than three well-known artists of Restoration England: conceived and begun by Antonio Verrio, who undertook many commissions for the English Court, it was completed by Godfrey Kneller, an anglicized German, and James Thornhill, who, against Wren’s wishes, had been commissioned to paint murals inside the dome of St Paul’s.
One of the most original of Wren’s achievements in astronomy was the fashioning of the earliest-known lunar globe. The globe derived from the lunar observations Wren began in Oxford in 1655 as a quantitative response to the Selenographia of Hevelius, published in 1647. The young Wren stressed that, unlike the leading telescopic observer of the previous generation, his lunar work would be based on measurement, through the application of the eyepiece micrometer. As he asserted in a lecture at Gresham College in 1657, we can depict the moon ‘with more Accurateness, than we can our own Globe.’
By 1661 Wren was at work on a lunar globe, which he completed in August. It was made of pasteboard, moulded in relief, and painted. It immediately entered the cabinet of King Charles II, where it joined Wren’s drawings of microscopical subjects, such an a louse and a flea, in the genre that was later adopted by his friend Robert Hooke.
The globe was shown to visitors to the royal collection, such as Balthazar de Monconys, Samuel Sorbière and Christiaan Huygens. Sorbière reports that ‘His Majesty put me upon admiring it’, while Huygens found it ‘very pleasant to look at, with all its spots and little round valleys’.
Historians of selenography have recognized the significance of Wren’s globe, long since lost, but have not realized that a contemporary illustration of it has survived. Historians of art, looking at Wren’s portrait, have taken the globe squeezed into the bottom right-hand corner beside the reverse-taper telescope, to be a terrestrial globe – the natural complement to the larger celestial globe shown in front of the view of the London skyline that Wren transformed.
However, the smaller globe, on its simple turned wooden stand, is definitely lunar. The celestial globe could have been modelled on any example the artists had available, but the lunar globe was unique. Was it sketched or painted from the original? Surely this is likely, from the way the light shows the markings rather than the relief in the portion directly illuminated, but picks out the craters just beyond the boundary of the shadow. In any case, Wren was very much alive at the time and will have wanted this very special globe, as he wanted the moon itself, to be accurately recorded.