Father Pietro Angelo Secchi, scientific adviser to the Pope, was asked by Commander Cialdi, head of the Papal Navy, to test a new transparency instrument. This instrument, now named the “Secchi” (rhymes with ekki, or Becky) disk, was first lowered from the papal steam yacht, l’Immacolata Concezione (The Immaculate Conception) in the Mediterranean Sea on April 20, 1865.
Secchi (1818–1878) was actually a famous astronomer, one of the first astrophysicists. A pioneer in the application of photography to astronomy, he photographed an eclipse of the sun in 1851. He was probably lucky that he did not gain recognition for his color map of Mars on which he labeled faint tracings as canali, the Italian word for “channels.” Another Italian, Giovanni Schiaparelli, expanded the number and legibility of the canali on his map. Later these canali, or channels, were misinterpreted to mean artificial canals, leading to speculation of life on Mars. In a sense, Secchi was the progenitor of some great (and not so great) science fiction.
For more information on Father Secchi:
- Catholic Encyclopedia (Biography in English)
- Wikipedia