Asaph Hall

Asaph Hall (Goshen, Connecticut, October 15, 1829 - Annapolis, Maryland, November 22, 1907) was an American astronomer. He discovered in 1877 the two satellites of Mars —Phobos and Deimos—, determined the orbits of numerous satellites, the motion of a series of binary stars, the rotation of Saturn, and the mass of Mars and other planets.

Biography

With little academic training, since after the death of his father he had to work as a carpenter to help his mother, his desire for knowledge and to study the sky led him to prepare himself. In 1857 he went to work as an assistant to the astronomer William Cranch Bond at the Harvard Observatory (Harvard College Observatory): the salary he had was twelve dollars a month.

In 1856 he married Angeline Stickney (1830 - 1892), who always supported him in his work.

After making numerous observations, learning astronomical techniques, and improving his knowledge, in 1863 he was appointed director of the Washington Naval Observatory (USNO), where he discovered the two satellites of Mars in August 1877, Deimos and Phobos, with the great 66 cm refractor of said observatory, the work of the American optician Alvan Clark. He had previously discovered the rotation period of Saturn. In 1895 he would occupy the post of professor of astronomy at Harvard University.

One of the largest craters on Phobos is named Hall in his honor; Stickney, named after his wife, is the largest and deepest in the satellite.

He had four children: Asaph Jr., Samuel, Angel, and Percival; only the first (Asaph Hall Jr.) would continue the family tradition by becoming an astronomer and carrying out numerous astronomical works; he published a large number of articles and celestial studies.

Posts

• Nebulae in the Pleiades, (1886), Astronomische Nachrichten, volume 114, p. 167.
• Observations on Mars, (1888), Astronomical Journal, vol. 8, iss. 181, p. 98-98.
• Observations of Mars, 1892, (1893), Astronomical Journal, vol. 12, iss. 288, p. 185-188.
• The orbit of the satellite of Neptune, (1898), Astronomical Journal, vol. 19, iss. 441, p. 65-66.
• Motion of the perihelion of Mercury, (1900), Astronomical Journal, vol. 20, iss. 479, p. 185-186.
• The differential equations of disturbed elliptic motion, (1906), Astronomical Journal, vol. 25, iss. 586, p. 77-79.

Acknowledgments

Gold Medal of the Royal Astronomical Society received by Hall

• Lalande Prize of the French Academy of Sciences in 1878.
• Gold Medal of the Royal Astronomical Society in 1879.
• Arago Medal in 1893.
• Nombarked Knight of the Legion of Honor in 1896.

Eponymy

• The lunar crater Hall carries this name in his memory.
• Likewise, the crater Hall on the Martian moon Fobos owes him his name.
• The asteroid (2023) Asaph and (3299) Hall was also named in his honor.

Font

• History of the Telescope, Isaac Asimov, Editorial Alliance (1986).
• NASA ADS (works, articles and publications)[1].