First photo of sunIn 1845, the first surviving daguerrotype photograph showing details of the sun was taken by French physicists Armand Fizeau and Léon Foucault. The 5-inch (12 cm) image had an exposure of 1/60 second, and showed the umbra/penumbra structure of several sunspots, as well as limb darkening. The photographic process was new: Daguerre perfected the daguerrotype only a few years earlier, in 1838. Fizeau and Foucault had been collaborating with their own experiments on the process since 1839. Fizeau had much improved the durability of a daguerrotype image with a treatment, published in Aug 1840, using a solution of chloride of gold mixed with hypo-sulphite of soda, then heated over a spirit-lamp.« |
