Cosmic Background Explorer
He was best known for his work measuring the Cosmic Microwave Background emission, providing upper limits on the CMB anisotropies, which began with observations on cold winter nights at Jodrell Bank Observatory in the late 1970s, before relocating his telescopes up the mountain on Tenerife in the early 1980s to take advantage of the clearer atmosphere at that location. By the early 1990s his instruments had detected the anisotropies of the CMB, however the publication of his results came after the results of the Cosmic Background Explorer had been announced; the COBE team went on to win the Nobel Prize for Physics for their discovery.