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| F. Arago, Popular Astronomy, Volume 2, Book XIV, Chapter XXVII, p176 (1855) |
The first successful photograph of the Sun was taken by the French physicists Louis Fizeau and Léon Foucault on April 2, 1845.For this, the solar light was reflected horizontally by a heliostat to a lens, at the focus of which a daguerreotype was placed. But the Sun is so bright that the exposure time was to be between 1/60 and 1/100 of a second: it was not possible to use the usual method of a cover removed and replaced manually on the lens. Fizeau and Foucault imagined an “original enough” shutter consisting of a plate with a horizontal slit of appropriate width, which they dropped in front of the camera: this was the ancestor of the curtain shutter. The picture showed sunspots aswell as limb darkening. The limb darkening was subject of debate those days.
Compare with my recent picture of the Sun, 179 years later :)
References:
- F. Arago, Popular Astronomy, Volume 2, Book XIV, Chapter XXVII, p176 (1855)
