The First Eclipse Photograph
On July 28, 1851, Prussian daguerreotypist Johann Julius Friedrich Berkowski captured the world’s first photograph of a total solar eclipse. He used the daguerreotype process, which exposes a silver‑coated copper plate and develops it with mercury vapor.
The image was likely made from a viewing site near Königsberg, where the eclipse was total. Besides the darkened solar disk, a bright halo is visible – the solar corona, visible to the naked eye only during totality and previously only sketched.
The picture sparked great interest among astronomers because it supplied objective details of the corona for the first time. Scientists inferred temperature and composition of the Sun’s outer atmosphere, advancing spectroscopy and laying groundwork for modern astrophysics.
Exposure lasted several minutes; Berkowski had to keep the telescope precisely aimed to avoid overexposing the bright photosphere. Despite the long exposure, the plate remained remarkably sharp, demonstrating the daguerreotype’s sensitivity under good lighting. After development, the image was stabilized with a gold chloride solution to enhance its longevity.
Today the daguerreotype is regarded as a milestone in solar research and an early example of how photographic technology transformed the observation of celestial events. The original plate is held in the archives of the Deutsches Museum in Munich and is occasionally displayed in exhibitions.