UH Institute for Astronomy Researcher Wins Prestigious Muhlmann Award of the Astronomical Society of the PacificUniversity of Hawaiʻi
Dr. François Roddier has been awarded the Maria and Eric Muhlmann Award of the Astronomical Society of the Pacific. This award honors scientists who have made important discoveries based on their work in developing new instruments and techniques.
Upon learning of the award, UH Institute for Astronomy Director Dr. Rolf-Peter Kudritzki remarked that "I was extremely pleased to learn Dr. François Roddier is the recipient of the very prestigious Muhlmann Award. Dr. Roddier pioneered the theory of adaptive optics and has played a key role in developing the field. His fellow colleagues at the University of Hawaii Institute for Astronomy join me in and congratulating Dr. Roddier on his significant achievements in the field of infrared astronomy". Dr. Tobias Owen, a senior faculty member and planetary astronomer at the UH Institute for Astronomy, explained that "adaptive optics is a revolutionary technique that allows ground-based optical/infrared telescopes, such as those located at the Mauna Kea Observatories on the Big Island of Hawaii to see the stars almost as if the Earth had no atmosphere"
Adaptive optics uses computers, actuators, and deformable secondary mirrors to correct the turbulence caused by Earth's atmosphere. The image of a star becomes blurred when it is viewed from the Earth's surface. Adaptive optics lets telescopes achieve an angular resolution that rivals, or even exceeds, that of the Hubble Space Telescope (HST). One way of avoiding atmospheric seeing problems is to place a telescope in orbit above Earth's atmosphere. But the HST is very expensive to use and has less than a tenth of the light-gathering power of the 8-10 meter telescopes of Mauna Kea. Following Dr. Roddier's lead, scientists and engineers have developed various techniques to improve the image quality of large ground-based telescopes so that they can compete with and outperform the HST.
The Institute for Astronomy's Adaptive Optics Group, which was led by Claude and François Roddier, built an elaborate system to improve the image quality of Mauna Kea telescopes. The light from the primary mirror of the telescope is reflected off a small flexible mirror, whose shape can be distorted by applying voltages to electrodes. A novel type of sensor (called a curvature sensor) constantly measures the deviations in the incoming wave-front from a plane surface. A computer rapidly calculates how to counteract these variations and adjusts the shape of the flexible mirror several hundred times a second. Star images with a width of 0.068 arcsecond (full width at half-maximum) have been obtained.
This brilliant and revolutionary, technique, which was developed by Dr. Roddier and his group, is so successful that it is now used on many of the world's largest infrared telescopes, such as the Gemini Northern 8-M Telescope, the 4.6 meter Canada-France-Hawaii Telescope, the 3.8 meter United Kingdom Infrared Telescope, the 3.0 meter NASA Infrared Facility, and the University of Hawaii's 2.2 meter Telescope, which are located on Mauna Kea.
Dr. Roddier has used his own equipment to conduct significant research into the birth and death of stars. He, and his collaborators at the Institute for Astronomy also made the first ground-based detection of Neptune's ring arcs and an asteroid satellite.
Dr. Roddier now resides in his native France since his retirement from the University of Hawaii Institute for Astronomy in December 2000.
Images: An adaptive optics image of the bipolar nebular Frosty Leo (IRAS 09371+1212) obtained at the Coudé focus of the CFHT telescope, as featured on the cover of the December 1994 issue of Physics Today, is available at
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