1818-1878

Italian priest and astronomer who created one of the earliest systems for classifying stars. Secchi classified over 4,000 stars by their spectra. Secchi also helped develop photography as an astronomical tool. He studied solar prominences and observed markings on Mars that he interpreted as canals, sparking the interest of other astronomers. In 1890 he correctly identified dark spaces in photographs of star fields as clouds of dark interstellar matter.