Comet Donati, or Donati's Comet, formally designated C/1858 L1 and 1858 VI, is a long-period comet named after the Italian astronomer Giovanni Battista Donati who first observed it on June 2, 1858. After the Great Comet of 1811, it was the most brilliant comet that appeared in the 19th century. It was also the first comet to be photographed. The comet will not be seen on Earth for another 1600 years.