An astronomer, Gillett was a pioneer in infrared observations, which allow astronomers to peek through interstellar dust clouds to see what’s behind. IR observations also allow clearer looks at stellar “nurseries”, where stars form. He was the project scientist for the International Gemini Observatory, a pair of specialized telescopes (one in Mauna Kea, Hawaii and the other in Cerro Pachon, Chile).
“He was the one who persuaded the astronomical community that infrared-optimized telescopes should be a top scientific priority,” said National Optical Astronomy Observatory colleague Sidney Wolff. “Then he carried out the detailed calculations that showed how to build them — the requirements for telescope design, mirror coatings, and instrument performance.”
Gillett, who was also heavily involved with the Infrared Astronomy Satellite (which mapped the Milky Way), was awarded NASA’s Exceptional Scientific Achievement Award in 1984 for his work on that project. He died April 22 from myelodysplastic disorder syndrome, a bone marrow disease. He was 64.