Huggins, Sir William

(1824–1910) British astronomer and astrophysicist: pioneered stellar spectroscopy and discovered stellar red shifts.

Huggins was a wealthy amateur who used his private observatory in South London to study a full range of celestial objects. Like , he was attracted by spectrum analysis and its possible use in astronomy; aided by his wife Margaret (1848–1915), Huggins pioneered the study of the spectra of stars, finding them to contain elements already known on Earth and in the Sun. He went on to investigate nebulae, making the important discovery that they were composed of luminous gas; he later showed that a comet contained hydrocarbon molecules. In 1868 he made perhaps his most profound discovery, observing that the spectrum of Sirius is shifted towards the red end of the spectrum. He correctly interpreted this as being due to the effect, obtaining a recessional velocity of about 40 km s –1 (25 miles per second), and proceeded to measure the red shifts of many other stars. With the advent of the gelatine dry plate he pioneered the technique of spectroscopic photography, from 1875. (The particular advantage of photography over the eye is that a faint image can be ‘accumulated’.)