Photographic glas slide, taken around 1858-1862, shows the half-phase of the Moon in its first quarter. The picture taken by Warren De La Rue (1815-1889), a pioneer of astrophotography, was obtained using the 13-inch reflecting telescope at his observatory at Cranford, Middlesex. This was a difficult task, as the wet collodion plates that were then available were de la Rue to make insensitive to light compared to modern films. This required exposures of several minutes through his telescope using a clock-driven equatorial mounting.
© Science Museum / Science & Society Picture Library