The Mills Cross Array, or the 96-acre antenna array, was a

Mills Cross Telescope The Mills Cross Telescope was a two-dimensional radio telescope built by Bernard Mills in 1954 at the Fleurs field station of the Australian Commonwealth Scientific and Industrial Research Organisation in the area known now as Badgerys Creek, about ...

-style

radio telescope A radio telescope is a specialized antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky. Radio telescopes are the main observing instrument used in radio astronomy, which studies the radio frequency ...

located in Seneca Maryland, near

Washington, D.C. ) , image_skyline = , image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan, ...

Constructed in June, 1954, it was operated by the

Carnegie Institution of Washington The Carnegie Institution of Washington (the organization's legal name), known also for public purposes as the Carnegie Institution for Science (CIS), is an organization in the United States established to fund and perform scientific research. Th ...

. The full array consisted of two arms, each 2047 feet in length with 66 dipole antennas. The dipole antennas were supported by unpainted wooden poles, connected with wires. The telescope had around of wire, with an army surplus truck housing the phase-switching radio receiver. It was built to conduct a 22.2 MHz (13.5 meter) sky survey, and at that frequency it had a beam about 2.5 degrees wide. In 1955 the array was used by Bernard F. Burke and

Kenneth Franklin Kenneth Linn Franklin (March 25, 1923 – June 18, 2007) was an American astronomer and educator. Franklin was the chief scientist at the Hayden Planetarium from 1956 to 1984 and was co-credited with discovering radio waves originating on Jupit ...

to discover 22.2 MHz radio emission from

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but ...

, which they tentatively attributed to

thunderstorm A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are someti ...

-like activity in Jupiter's atmosphere. Although radio waves had been detected from astronomical sources as early as 1931, this was the first detection of radio waves from another planet. The field where the array was located is now part of the

McKee-Beshers Wildlife Management Area McKee-Beshers Wildlife Management Area is a Wildlife Management Area in Montgomery County, Maryland. It is a large contiguous forest of varied habitat, situated between the Potomac River and the Chesapeake & Ohio Canal to the south, and Seneca Cree ...

References

Radio telescopes {{Observatory-stub