To capture the Moon
By Tony Simcock and Scott Billings
The Museum’s Moonstruck exhibition (14 October 2014 – 5 April 2015) has set us on the trail of other things that carry the Moon theme further than the material on display, sometimes in unexpected directions. Of course there’s nothing unexpected about the Museum having historic instruments related to scientific research. Even so, the trail that started from a casual remark that it would be interesting to know more about the ‘Moon Camera’ (as the label calls it) in the Museum’s permanent displays has led from one astonishing find to another, to another, and taken us truly into the depths of the collection …
De la Rue’s ‘Moon camera’ (inv 81324)
The camera in question, shown left, is obviously something rather unconventional, not at all the shape of anything you’d normally call a camera. This is because – it’s obvious once you think about it – it isn’t used independently; it’s essentially an attachment for a large telescope. The label says its date is about 1854, so that places it quite soon after the invention of photography in 1839. In fact, photography couldn’t be expected to tackle the Moon properly until glass plates sensitised with wet collodion were introduced, which was in 1851. This made the process faster and more sensitive to detail.
There are actually three such cameras in the collections, each a different size and shape. The other two are larger than the one displayed, one round and one square. They all have in common, however, the peculiar feature of handles or wings sticking out either side. They are actually brackets, because the cameras have to be fitted across the diameter of the telescope tube, which is 13 inches (33cm) wide. They’re from the famous De la Rue telescope, and – surprise surprise – we don’t just have the cameras, we have the entire telescope. Turns out it’s the largest single object in the collection, though for that very reason it’s dismantled and kept in storage.
The De la Rue telescope tube (inv 73180) in the Museum store
Deep in the furthest corner of the Museum’s off-site storage facility, there it sits, in many separate pieces but – we’re assured – all there, right down to the nuts and bolts. It wasn’t, however, used chiefly for looking through. That’s the crucial thing that makes it historically important, and that’s where the cameras come in.
Hot on the heels of the invention of photography, wealthy businessman, inventor, and amateur astronomer Warren De la Rue (1815-1889) set about designing this large telescope for his own private observatory near London. It was completed in 1849, and improved when he moved to a better observatory nearby in 1857. De la Rue wasn’t the first to take photographs through a telescope; but his telescope was, so far as we know, the first to be designed and built with photography in mind.
The cameras are indeed, therefore, truly pioneering and unique. Strictly speaking they are more like glorified plate-holders, since the telescope itself acts as their lens, focusing its image onto a glass plate, sensitised by the collodion process and used wet (that is, immediately after being coated with the photographic emulsion). The camera’s main function is to hold this glass plate at the focal point, fine focus it, and protect it from any other light that will spoil the image.
The De la Rue ‘Moon camera’ in use circa 1930; image reproduced here for the first time
Because of the way a ‘reflecting’ telescope works, with the mirror at the bottom end of the tube, the camera is mounted near the top end, 10 feet away. The vintage photograph showing the telescope in about 1930 illustrates this arrangement. Oxford astronomer Frank Bellamy is standing on a platform and fiddling with fittings near the top end of the open-work tube. That’s also where he would go to look through it (the ‘finder-scope’ mounted on the side is just for positioning purposes). The camera goes across the diameter of the tube near where his hand is – we can’t quite decide, but the object visible in that position to the left of his hand may be one of the cameras.
This 1930-ish photograph is itself a rare treasure, one of a small group of glass negatives identified only recently among the Museum’s large photographic collection. De la Rue gave his telescope to the University of Oxford in 1873, so it had a second lease of life in university teaching and research. Finally, in the early 1930s, shortly after this photograph was taken, it was dismantled and – narrowly escaping the scrap-metal dealer – transferred to the custody of the Museum. It was thought that no photographs existed showing it in situ at Oxford, so this recently-discovered image (scanned directly from the glass negative) has never been reproduced before.
A stereoscopic transparency of the Moon, taken with De la Rue’s camera
Of course, we also have a few photographs taken with De la Rue’s telescope. What are they of? It doesn’t take much guessing. The Moon wasn’t De la Rue’s exclusive purpose. ‘Celestial’ photography, as astronomers like to call it, sounds glamorous; but endless plates showing nothing but pin-prick stars became the bedrock of the new era of mapping the universe that photography brought with it. But whether for glamour or for scientific relevance, for gazing at or for studying, our nearest celestial neighbour and companion had no rival in the early days of photographic astronomy. De la Rue’s photographs of the Moon were what made his telescope truly famous, in its day, and copies were sold commercially through the instrument manufacturer Smith & Beck. The stereoscopic transparency illustrated above is one of these.
Here’s one that’s a bit more interesting though – we’re in the Museum library, carefully unwrapping a precious little circle of glass, 2¾ inches (70mm) in diameter. In the middle is a half-moon just 1 inch (26mm) in diameter. It’s an original negative taken in the De la Rue telescope on 27 March 1863.
A negative of the Moon, taken with De la Rue’s camera
Being ‘negative’ – the sky white not black – doesn’t matter for scientific purposes; in fact the image is better. The date and other data are scratched onto the glass by De la Rue himself. The detail of the Moon’s surface is excellent – many individual craters can be seen with great clarity.
But you know what’s really special about this particular photograph? With its small size and unusual circular format? That’s right – it matches the plate-holder – the widest part – of the De la Rue camera above exactly. So it was taken with the very camera displayed in the Museum. The size of the Moon’s disc wouldn’t vary much in the De la Rue mirror. So while the larger square camera in store was for star mapping, the camera on display, with its small cylindrical body, was, as its label rightly says (did we ever doubt it?), specifically designed for photographing the Moon.
Moonstruck? You bet we were.
