PROCEEDINGS ARTICLE | July 10, 2008
Proc. SPIE. 7012, Ground-based and Airborne Telescopes II
KEYWORDS: Telescopes, Mirrors, Cameras, Sensors, Image quality, Domes, Humidity, Turbulence, Infrared telescopes, Optical instrument design
PILOT (the Pathfinder for an International Large Optical Telescope) is a proposed Australian/European optical/infrared
telescope for Dome C on the Antarctic Plateau, with target first light in 2012. The telescope is 2.4m diameter, with
overall focal ratio f/10, and a 1 degree field-of-view. It is mounted on a 30m tower to get above most of the turbulent
surface layer, and has a tip-tilt secondary for fast guiding. In median seeing conditions, it delivers 0.3" FWHM wide-field
image quality, from 0.7-2.5 microns. In the best quartile of conditions, it delivers diffraction-limited imaging down
to 1 micron, or even less with lucky imaging. The major challenges have been (a) preventing frost-laden external air
reaching the optics, (b) overcoming residual surface layer turbulence, (c) keeping mirror, telescope and dome seeing to
acceptable levels in the presence of large temperature variations with height and time, (d) designing optics that do
justice to the site conditions. The most novel feature of the design is active thermal and humidity control of the
enclosure, to closely match the temperature of external air while preventing its ingress.
