15 February
1858: On 15 February 1858, William Henry Pickering was born.
Pickering was an American astronomer who discovered Phoebe, the ninth moon of Saturn. This was the first planetary satellite with retrograde motion to be detected. Retrograde orbits are orbits in the opposite direction to that of the planets.
He made extensive observations of Mars and claimed that he saw signs of life on the planet by observing what he took to be oases in 1892. By comparing descriptions of the Moon from Giovanni Riccioli's 1651 chart onward, he thought he had detected changes that could have been due to the growth and decay of vegetation.
