Karl Jansky (1905 - 1950), electrical engineer, and pioneer in the field of radio astronomy. He was an engineer at Bell Telephone Laboratories in Holmdel, New Jersey. He was studying how to determine the location of thunderstorms based their static noise bursts in radio receivers, with the ultimate goal of developing low-noise, directional receivers for transoceanic communications. He designed a track-mounted, vertically-polarized wire antenna grid, to measure the amount of noise as a function of the antenna's orientation and the time of day. The antenna was rotated on its circular track once every twenty minutes, and the total received power measured with a strip chart recorder, 24 hours a day.

While he was able to successfully locate thunderstorms both locally and worldwide, he also found a daily modulation in the amount of noise the origin of which he could not immediately determine. Measurements over a long period of time determined that the source of the noise was not only extraterrestrial, but extra-solar, coming instead from the center of the Milky Way Galaxy, which he detected at 10 (30 MHz) and 14.6 meters (20.6 MHz). He published this work in three papers in the Proceedings of the Institute of Radio Engineers (later to become the IEEE) in December 1932 (v. 20, p. 1920), October 1933 (v. 21, p. 1387), and October 1935 (v. 23, p. 1158). Unfortunately, the significance of this work was not immediately recognized, and radio astronomy did not come into its own until the work of fellow radio engineer Grote Reber in the early 1940s. His plans for building a truly directional, parabolic dish and receiver weren't pursued by Bell Labs, and he was transferred to other projects within the company.

Jansky died prematurely of a stroke at the age of 45.

He has been honored by having a unit of measurement - the Jansky - named for him. The American Astronomical Society and NRAO also bestow the Jansky award for outstanding achievements in the field of astronomy, and NRAO also awards several Jansky Fellowships to outstanding postdoctoral researchers in the field of radio astronomy.

Sources: various, including Radio Astronomy by J. D. Kraus (Powell, Ohio: Cygnus-Quasar Books, 1986)