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Summary

It is currently operational at South Pole station, and will later be deployed to remote, uninhabited sites on the high Antarctic plateau. It has a suite of astronomical site-testing instruments, so that potential observatory sites can be fully characterized over a wide range of wavelengths.

In addition to the astronomical site-testing data, the AASTO also collects weather data such as temperature, wind speed and direction, and atmospheric pressure.

The AASTO package consists of a suite of instruments:

Near-Infrared Sky Monitor (NISM)

This is the simplest instrument, with an InSb detector and fixed 2.35 micron filter cooled to 77K by a low-power Stirling cooler. NISM is designed to make only "Sky-dip" measurements. Placed to one side of the instrument is a black-body calibration source.

Mid-Infrared Sky Monitor (MISM)

The MISM is similar in concept to its near-IR counterpart, but uses a Stirling-cycle cooled HgCdTe detector. A chopping frequency of 1kHz is used to avoid 1/f noise. An ambient-temperature filter wheel yields spectral coverage from 4 to 14 microns.

Antarctic Fiber-Optic Spectrometer (AFOS)

The AFOS consists of a small telescope feeding a grating spectrometer and CCD detector via a bundle of six optical fibers. By observing bright stars, a direct measure of atmospheric transmission from the UV cut-on to about 800 nm is obtained. In addition, sky emission arising from aurorae and airglow can be monitored.

A full description of the AFOS, together with preliminary results, has been prepared by Boccas et al. (1998).

Sonic Radar (SODAR)

Acoustic radar which measures the height of the turbulent atmospheric boundary layer. Deployed in January 1999, it acquired several weeks of wind and microthermal data with 20 meter resolution to a height of up to 800 meters.

Generic Telescope Mount and DIMM (G-MOUNT and ADIMM)

Instruments under development by Australian National University for deployment in January 2000 to measure the seeing.

Submillimeter Tipper (SUMMIT)

Constructed by Carnegie Mellon University and the National Radio Astronomy Observatory and loaned to the AASTO project, the submillimeter tipper uses an ambient-temperature pyroelectric detector to monitor 350 micron radiation. A stepper motor drives an off-axis paraboloid mirror, allowing the instrument to scan from zenith to horizon. The tipper is currently taking data on the roof of the AST/RO building at the South Pole. Modifications to the tipper are planned to incorporate it within the AASTO package of instruments. For more information, see the submillimeter tipper website.

Results

• Measurement of the near-infrared sky brightness from 1.5 microns to 5.5 microns and monitoring it throughout an entire year (Phillips et al 1999).
• Measurement of the mid-infrared sky brightness from 4 microns to 14 microns and monitoring it throughout an entire year (Chamberlain et al. 1999).
• Measurement of the near-ground microthermal atmospheric turbulence (Marks et al. 1996).
• Balloon-borne measurement of microthermal turbulence throughout the atmosphere (Marks et al. 1996).

Pictures

• Our virtual tour has pictures.
• The group's website also has pictures.

For more information

AASTO is based at the University of New South Wales, Australia, as part of JACARA, the Joint Australian Center for Astrophysical Research in Antarctica. For more information, contact Michael Ashley, mcba@newt.phys.unsw.edu.au.

CARA's research and education programs are supported in part by the National Science Foundation under a cooperative agreement, grant number NSF OPP 89-20223. © Copyright 1998,1999,2000 by Center for Astrophysical Research in Antarctica. This copyright applies to all web pages and images created by CARA.