John Gatenby Bolton

Learning to work with radio instruments

Bolton was born in Sheffield and trained in physics. Wartime radar work gave him experience with receiving signals, identifying interference and using instruments outside a laboratory. He went to Australia and joined the radiophysics programme in which scientists were beginning to use wartime equipment to study celestial sources. One challenge was to tell a source with a definite direction from changes in the equipment or its surroundings.

A radio signal did not arrive with the name of a visible object attached. To make a connection with optical observations, the radio measurement needed a position precise enough to test proposed matches.

Sources for this section: [1] · [3]

Positions measured from the coast

Bolton worked with Gordon Stanley and Bruce Slee on discrete radio sources. Their 1949 paper reports improved positions derived from observations on the coasts of Australia and New Zealand. At suitable sites, patterns observed as a source rose or set helped the team estimate its position. They accounted for atmospheric refraction before inferring celestial coordinates.

The results let astronomers consider optical objects in the same regions. A position match was important evidence, while identifying the physical source required further work. The paper’s title uses the language of its own period. It should not be taken as a modern classification of all the sources it discussed.

Sources for this section: [1] · [2]

From individual observations to a facility

Bolton continued his career in Australia and the United States. He became the first director of the Parkes telescope and helped establish how researchers would use a large, dedicated radio observatory. His work spans two stages of the field. Coastal sites made early positional measurements possible. A permanent facility supported a wider range of observations that others could repeat and extend.

Sources for this section: [1] · [3]