| Description |
Adaptive Optics (AO) is a prime example of how progress in observational
astronomy can be driven by technological developments. Ground-layer adaptive
optics (GLAO) is a potentially unique and powerful AO technique which promises
modest wave-front correction over wide fields of view. This technique, where
only the atmosphere turbulence close to the ground is corrected, has now been
used to improve wide field imaging for large telescopes. Experiments have
shown that at the telescope sites on Mauna Kea in Hawaii, which is one of the
finest astronomical sites in the world, the atmospheric turbulence induced
optical aberrations, or seeing, is primarily made up of a ground layer and a
high atmosphere layer. This talk discusses measurements that have been made
late last year through the University of Hawaii 2.2 meter and CFHT 3.6 meter
telescopes to collect data that would predict the performance of a 1 degree
field-of-view adaptive optics corrected imager in support of the IMAKA/CFHT
project. This represents a few orders of magnitude improvement in field
coverage over present adaptive optics systems. Enhanced resolution over a wide
field would bring many advantages. The other important aspect of GLAO is that
it can function even in poorer atmospheric conditions where high order AO
struggles.
About the Speaker:
Dr. Douglas W. Toomey has been developing and building cameras and
spectrometers for Infrared astronomy in the 1 to 20 micron band with special
emphasis on the 1 to 5 micron band at the NASA Infrared Telescope Facility
(IRTF) on Mauna Kea, Hawaii. At the University of Hawaii, he has developed
many new techniques for designing instruments that measure infrared radiation.
His scientific investigations include observations of the Galactic center, and
imaging of Io occultations. In 1985, he started Mauna Kea Infrared LLC to
build custom hardware for specialised astronomy projects on large telescopes
around the world.
He has developed the Near Infrared Coronagraphic Imager (NICI) which is a
state of the art instrument on the Gemini 8 metre telescope in Chile focussed
on imaging Jupiter class planets orbiting around other stars. At present, he
is collaborating with the Infrared Astronomy Group of TIFR, in the TIRSPEC
project which involves installing a Near Infrared Spectrometer at the focal
plane of the 2 metre Himalayan Chandra Telescope (HCT) at Hanle, Ladakh.
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