Australian Dictionary of Biography

William Bolton Rimmer (1882-1945), astronomer and public servant, was born on 9 November 1882 at Fazakerley, Lancashire, England, son of John Rimmer, farmer, and his wife Sarah Jane, née Bolton. William studied engineering at University College, Liverpool (B.Sc., 1903; M.Sc., 1906; Victoria University of Manchester), and worked as a surveyor in British Columbia, Canada. Enlisting in the Royal Engineers in 1916, he was commissioned in June 1917 and promoted captain in July 1919. After he was demobilized he decided to become an astronomer and carried out spectroscopic research at the Imperial College of Science, Kensington, London.

In 1921 Rimmer obtained a position as research assistant at the Norman Lockyer Observatory, a small, private astrophysical establishment near Sidmouth, Devon. Selected as assistant to Dr W. G. Duffield, director of the newly established Commonwealth Solar Observatory at Mount Stromlo, Federal Capital Territory, he sailed for Australia and joined the observatory staff in December 1924. In the sacristy of St Gregory's Catholic Church, Queanbeyan, New South Wales, on 14 June 1927 he married 29-year-old Kathleen Anne Hayes.

Until 1939 Rimmer was the only trained astronomer at Mount Stromlo; the other four or five staff-members were solar or geo-physicists. In 1926-29 his chief astronomical task was to photograph spectra of the brighter stars, especially in the southern sky, using the Oddie 9-inch (23 cm) refracting telescope. For this purpose, the telescope had been provided with a glass prism which fitted over its objective to form spectra of stars in the focal plane, where they could be photographed. Over two thousand such spectra were obtained. They were used to estimate absolute magnitudes (luminosities or candle-powers) of the stars, mainly from the appearance of hydrogen lines in their spectra. Rimmer's account of this work—an extensive investigation which did him credit—was only the second paper to be published from the new observatory. For more than twenty years his study remained the only substantial astrophysical programme that had been carried out in Australia.

When Duffield died suddenly in August 1929, it was decided to economize by appointing no new director. Rimmer was made officer-in-charge, a position to which he could hardly have aspired in the ordinary way. With the added responsibilities the post entailed, his research had to be limited to maintaining two programmes concerning the sun. In the first, the sun's brightness was observed around noon every clear day with a pyrheliometer to determine whether its radiation was constant or whether it varied with, for example, the sunspot cycle. In the second programme, a pyranometer made a continuous record of the heating of the earth by the energy supplied by the sun, either directly, or as diffused by the sky and clouds. The results were of interest to agriculturists, meteorologists and others. Measurements in both projects continued until the outbreak of World War II.

Rimmer had been appointed O.B.E. (1938) for his services to astronomy. A new director was finally selected in 1939 and Rimmer was redesignated first assistant. He was president (1940-41) of the Royal Society of Canberra and a member (from 1930) of the local branch of the Professional Officers' Association, Commonwealth Public Service. He also belonged to Rotary. Survived by his wife, he died of a cerebral haemorrhage on 2 July 1945 at Mount Stromlo and was buried in Canberra cemetery with Baptist forms.