Brück, Hermann Alexander (1905–2000), astronomer and science administrator, was born 15 August 1905 in Berlin, only child of Hermann Heinrich Brück, army officer, and his wife Margarete Weylandt. He attended school at the Kaiserin Augusta Gymnasium, Berlin, and the universities of Kiel (1924), Munich (1924–5, 1925–8, magna cum laude in physics, mathematics and astronomy), Bonn (1925), Berlin (1935, D.Phil. habilitat.) and Cambridge (1938–41, Ph.D.). At Munich he completed a D.Phil. thesis in 1928 on the quantum mechanics of crystals supervised by Arnold Sommerfeld; Brück was a member of his research seminar.
Initially a research fellow in the Einstein Institute of the Astrophysical Observatory, Potsdam from 1928 to 1930, he then joined the permanent staff as assistant and pursued the new science of spectral classification of stars. Strongly opposed to the Nazi regime, Brück left Germany in 1936 for a temporary post at the Vatican Observatory where he continued spectral classification work. He then moved in 1937 to a long and fruitful stay in the group around Sir Arthur Eddington at Cambridge. In time he became assistant director of the observatories, and John Couch Adams astronomer.
At the invitation of Taoiseach Éamon de Valera (qv), he took charge of the moribund Dunsink Observatory in 1947, as part of the new DIAS, instigated by de Valera. The re-opening of Dunsink Observatory was a cherished ambition of de Valera's and he remained a staunch supporter of Dunsink and a personal friend. At the institute Brück's fellow professors were Erwin Schrödinger (qv) and Walter Heitler (qv), with whom he maintained close links and shared common scientific interests. After the observatory was transferred to state ownership and attached to the institute, Brück transformed it into a centre of modern observational technique, installing a large solar telescope and spectrograph as its principal instruments and concentrating on photoelectric photometry and solar spectroscopy extending to the ultraviolet. Collaboration with Armagh and Harvard College Observatories was fostered to develop the observing station in South Africa and a large Schmidt telescope was completed there in 1950.
The innovative and collaborative activities were recognised when the International Astronomical Union (IAU), in a state of post-war east–west tension and unable to agree on a meeting place, approached Brück with the request that Ireland, a neutral country acceptable to all members, should host the triennial assembly. In consequence the IAU meeting held in Dublin in 1955 was very successful.
Brück's last move in 1957 was to the Royal Observatory Edinburgh where he assumed the Regius chair of astronomy and the title astronomer royal for Scotland. Here he again transformed the observatory, aware that the new electronic age would revolutionise the subject. He gathered around him a team of innovative scientists and engineers to pioneer the new automated methods in astronomy, both for telescope control and for machines to analyse photographs of star and galaxy images and their spectra. This type of instrumental development is still central in the role of the Royal Observatory. He established an observing station at Monte Porzio near Rome as a first step to moving observatories to better climates. Later the Royal Observatory Edinburgh operated the UK Schmidt telescope at Siding Spring in Australia.
At a critical time for British observational astronomy, and as the Anglo-Australian Observatory was coming into being, Brück first proposed building a large telescope (150 inch diameter) in the Northern hemisphere in 1965. The deliberations over the organisation of such a facility by the Northern hemisphere review committee during 1969–70 were protracted, and constituted the only anxious period of his career when the future of the royal observatories appeared to be under threat. Site testing began under Edinburgh management and the final outcome was the Northern Hemisphere Observatory operated by the Royal Greenwich Observatory on La Palma. During this empyrean phase, the Royal Observatory Edinburgh was charged with commissioning and operating the UK infrared telescope in Hawaii. This was the first four-metre class telescope entirely devoted to infrared observations and had a major impact on the direction of astrophysical research. In parallel with this scientific development, Brück expanded astronomy teaching at the university, with a new honours degree in astrophysics starting in 1967. He was an enthusiastic teacher and encourager.
Brück was the recipient of various honours and distinctions: CBE (1966), D.Sc.(hon.) NUI (1972), D.Sc.(hon.) St Andrews (1973), KGC Order of St Gregory the Great (1995). He was a member of the RIA (1948), the Pontifical Academy of Sciences (1955, council 1964–86), a corresponding member of the Academy of Sciences (Mainz, 1955), and a fellow of the Royal Society of Edinburgh (1958, council 1959–62).
In 1936 Brück married Irma Waitzfelder (d. December 1950), daughter of Ignatz and Elsa Waitzfelder, linen merchants; and in 1951 he married Maire (Mary) Teresa Conway, daughter of Thomas and Margaret Conway, school teachers. He was survived by three daughters and two sons. Maire Brück was an astronomer and with her husband wrote The peripatetic astronomer: the life of Charles Piazzi Smyth (1988), and made several other historical contributions on her own.
After an intellectually lively retirement, Brück died in Edinburgh 4 March 2000. Brück's papers can be found c/o Dr M. T. Brück and in the Royal Observatory Edinburgh. There is a photographic portrait of Brück at the Royal Observatory.