Multimeters Monitor Telescopes at Antarctic Temperatures
July 2, 2009
The brief Antarctic summer gives astronomers little time to maintain the equipment at their telescope test site in the remote Antarctic interior. They demand tools they can rely on and have been using digital multimeters from Everett, Wash.-based Fluke.
Since 1996, astronomers from the University of New South Wales have sought the perfect location for the next generation of deep-space telescopes. They may have found it in perhaps the most difficult environment on Earth - 621 miles from the Antarctic coast and 10,695' above sea level. During the sunless winter, temperatures in the interior can reach -112°F (-80°C) or lower.
For the purposes of astronomical "seeing" however, the location is ideal. Australian astronomers have successfully demonstrated that their site has viewing conditions nearly as good as that of the orbiting Hubble telescope.
Because the astronomers only can reach the site in summer, their automated telescope equipment must operate unattended the rest of the year, reliably producing accurate measurements. The equipment is a custom mixture of analog and digital electronics developed to withstand extreme and variable winter temperatures. Fluke's 189 and 179 digital multimeters form a key part of the installation and maintenance tool kit.
In trips to Antarctica each summer, the researchers use the multimeters to test and set up the astronomical instruments and supporting electronic and electrical systems, as well as to conduct voltage, resistance and temperature measurements. The multimeters are used in outdoor ambient temperatures generally between -20 to -40°F (-30 to -40°C) and indoors at about 50°F (10°C). Then they leave several Fluke tools on site to monitor operations in their absence.
"From experience, we've found cheap multimeters are susceptible to radio frequency interference when used near switchmode power supplies, for example," says the university's astronomer Michael Ashley. "And their accuracy suffers as their batteries decline, as well as having other display accuracy problems. We need instruments that work, from which we can guarantee results. We've never had a problem with Fluke instruments."