Fred Gillett, who pioneered infrared astronomy, died on April 22 at a hospital in Seattle. Formerly of Tucson, Ariz., he was 64 and lived in Hilo, Hawaii. The cause was a rare bone-marrow disease, said the National Optical Astronomy Observatory in Tucson. Dr. Gillett was on the observatory's staff and on the staff of Kitt Peak National Observatory, which is near Tucson, from 1973 to 1989, including a period as acting director at Kitt Peak. He was among the earliest proponents of infrared astronomy, in which the physics and chemistry of celestial objects are revealed by the heat they emit.
Infrared astronomy enables scientists to make discoveries beyond the range of visible light.
In 1994, he became the project scientist for the International Gemini Observatory, which operates a pair of eight-meter telescopes in Mauna Kea, Hawaii, and Cerro Pachon, Chile. He was largely responsible for using the twin instruments together for optimal results. The effort was known as the Gemini Project, and Dr. Gillett was on the international scientific committee that planned it. He was the one who persuaded the astronomical community that infrared-optimized telescopes should be a scientific priority. Then he carried out the detailed calculations that showed how to build them the requirements for telescope design, mirror coatings, and instrument performance.