A photograph of the Sun during a lunar eclipse, from a booklet by John Titterton entitled 'Autographs of the Sun', taken with the Heliautograph of Reverend William Selwyn of Ely, in 1861 and 1862. The photographer has also noted other numbers which probably relate to the time it was captured. This information was vital for recording patterns of change in the Sun's appearance. This series of photographs draws particular attention to the sunspots that photographers attempted to record with great interest. Sunspots are regions of unusually high magnetic field in the photosphere. Cooler than the surrounding areas, they look darker, appearing and disappearing periodically. Research into the sun in the 1850s and 1860s prompted calls for photographers to assist in recording details.
© National Media Museum / Science & Society Picture Library