Dr. Francois 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. Francois 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

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 Francois 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 Coude focus
of the CFHT telescope, as featured on the cover of the
December 1994 issue of Physics Today, is available at
http://www.ifa.hawaii.edu/ao/. See Roddier et al. 1995,
ApJ, 443, 249 for more details. Other adaptive optics
images are also available on the website.

The Institute for Astronomy at the University of Hawaii
conducts research into galaxies, cosmology, stars, planets,
and the Sun. Its faculty and staff are also involved in
astronomy education, deep space missions, and in the
development and management of the observatories on
Haleakala and Mauna Kea.
Refer to http://www.ifa.hawaii.edu for more information.