Inspired by G. R. Kirchhoff’s achievements, he carried out a series of pioneering spectroscopic observations, helped first by the chemist William Allen Miller (1817–70) and later by his wife, Margaret Lindsay Huggins, née Murray (1848–1915). By 1863 he had several stellar spectra, showing that the stars, like the Sun, consisted of incandescent gas and contained the same chemical elements as are found on Earth. In 1864 he detected green lines in the spectrum of the Orion Nebula which confirmed that it is gaseous, although he attributed the bright lines to an unknown substance which he termed ‘nebulium’. These early observations were all made visually; later he turned to photography as photographic plates improved. Huggins investigated many other objects spectroscopically, including comets, meteors, and novae.