Ronald N. Bracewell

Ronald Newbold Bracewell AO (22 July 1921 – 12 August 2007) was the Lewis M. Terman Professor of Electrical Engineering of the Space, Telecommunications, and Radioscience Laboratory at Stanford University.

[citation needed] From October 1949 to September 1954, Dr. Bracewell was a senior research officer at the Radiophysics Laboratory of the CSIRO, Sydney, concerned with very-long-wave propagation and radio astronomy.

For experimental contributions to the study of the ionosphere by means of very low frequency waves, Dr. Bracewell received the Duddell Premium of the Institution of Electrical Engineers, London in 1952.

Experience with numerical computation of fields in cavities led, after the war, to a Master of Engineering degree (1948) and the definitive publication on step discontinuities in radial transmission lines (1954).

While at Stanford, Professor Bracewell constructed a microwave spectroheliograph (1961), a radio telescope comprising 32 10 ft dishes arranged in a cross,[1] which produced daily temperature maps of the Sun reliably for eleven years, the duration of a solar cycle.

The first radio telescope to give output automatically in printed form, and therefore capable of worldwide dissemination by teleprinter, its daily solar weather maps received acknowledgement from NASA for support of the first crewed landing on the Moon.

Knowing that Centaurus A was composite, Bracewell used the 6.7-minute beam of the Parkes Observatory 64 m radio telescope at 10 cm to determine the separate declinations of the components and in so doing was the first to observe strong polarisation in an extragalactic source (1962), a discovery of fundamental significance for the structure and role of astrophysical magnetic fields.

Upon the discovery of the cosmic background radiation: With the advent of the space age, Bracewell became interested in celestial mechanics, made observations of the radio emission from Sputnik 1, and supplied the press with accurate charts predicting the path of Soviet satellites, which were perfectly visible, if you knew when and where to look.

Following the puzzling performance of Explorer I in orbit, he published the first explanation (1958–59) of the observed spin instability of satellites, in terms of the Poinsot motion of a non-rigid body with internal friction.

Later (1978, 1979) he invented a spinning, nulling, two-element infrared interferometer suitable for space-shuttle launching into an orbit near Jupiter, with milliarcsecond resolution, that could lead to the discovery of planets around stars other than the Sun.

This concept was elaborated in 1995 by Angel and Woolf, whose space-station version with four-element double nulling became the Terrestrial Planet Finder (TPF), NASA's candidate for imaging planetary configurations of other stars.

This method, which has advantages over the fast Fourier algorithm, especially for images, is treated in The Hartley Transform (1986), in U.S. Patent 4,646,256 (1987, now in the public domain), and in over 200 technical papers by various authors that were stimulated by the discovery.