William Henry Pickering

William Henry Pickering (February 15, 1858 – January 16, 1938) was an American astronomer. Pickering constructed and established several observatories or astronomical observation stations, notably including Percival Lowell's Flagstaff Observatory. He spent much of the later part of his life at his private observatory in Jamaica.

William Pickering was born on February 15, 1858, in Boston, Massachusetts. His parents were Charlotte (née Hammond) and Edward Pickering. His older brother was Edward Charles Pickering, director of the Harvard College Observatory from 1876 to 1920.

He attended secondary schools in Boston and Cambridge. In 1878, he published his observations of the coronal polarization of the 1878 solar eclipse in Colorado.

He graduated from the Massachusetts Institute of Technology (MIT) with a bachelor in science in 1879.

Pickering was an instructor in physics at MIT from 1880 to 1887. As early as 1882, pioneered in celestial photography. In 1883, he was elected a Fellow of the American Academy of Arts and Sciences at the age of 25.

In 1887, he became an assistant professor of astronomy at the Harvard College Observatory, teaching there until 1893. He either led or participated in Harvard's solar eclipse expeditions in Grenada in 1886, California in 1889, Chile in 1893, Georgia in 1900, and New England in 1932. In 1888, he took some of the first photographs of Mars.

He selected the site for the Mount Wilson Observatory of Los Angeles County, California in 1889. In 1891, he established the Boyden astronomical station for the Harvard College Observatory in Arequipa, Peru. In 1894, he set up the Lowell Observatory and telescope for Percival Lowell in Flagstaff, Arizona.

Pickering discovered Saturn's ninth moon Phoebe in 1899 from plates taken in 1898. In 1900, he established an astronomical station for the Harvard College Observatory in Mandeville, Jamaica. He produced a photographic atlas, The Moon: A Summary of the Existing Knowledge of our Satellite, in 1903. In 1905, he conducted studies of volcanic craters in Hawaii, noting their similarity to those of the moon. This was followed by similar studies in Canada, Alaska, and the Azores.