Annie Jump Cannon

Annie Jump Cannon 1863-1941, American astronomer, b. Dover, Del. In 1897 she became an assistant in the Harvard College Observatory, where (1911-38) she was astronomer and curator of astronomical photographs. Recognizing that spectra of many stars had been photographed in the second half of the 19th cent., Cannon classified more than 500,000 stars, in the process publishing many papers on the subject. One of the most significant achievements in 20th-century astronomy and the basis for contemporary theoretical understanding of stellar evolution, the catalog, named after its patron Henry Draper, is still in use. In the course of her photographic work she discovered 300 variable stars, 5 novas, 1 spectroscopic binary, and many stars with bright lines or variable spectra. In 1896 she discovered SS Cygni, a "dwarf nova" that repeats its outbursts about every 60 days. She made a bibliography of variable stars that includes about 200,000 references. Each year the American Association of University Women presents the Annie J. Cannon Award for distinguished contributions to astronomy.

Cannon, AnnieJump (1863–1941)Americanastronomer. In 1896 she began work under E. C.Pickering at the Harvard College Observatory, where she undertook the classification of stellar spectra. She refined W. P.Fleming's alphabetical sequence (A, B, C, etc.), dropping some categories and rearranging to yield a continuous series of spectral types: from hot O and B stars, through A, F, and G, to cool K and M stars. Cannon's classifications of the spectra of over 225 000 stars were published in the Henry Draper Catalogue.

can·non·ball / ˈkanənˌbôl/ • n. a round metal or stone projectile fired from a cannon in former times. ∎  (also cannonball dive) a jump into water performed upright with the knees clasped to the chest.