Great Movie of ATCA Reconfiguration September 2, 2009
Posted by astroed in Astronomy.Tags: Astronomy, ATCA, telescope
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Here’s a great question for trivia competitions.
Q: What is Australia’s widest gauge track?
A: Forget those massive iron ore trains in WA, Australia’s widest gauge track is actually in Narrabri, northern NSW at the Australia Telescope Telescope Compact Array (ATCA), part of the CSIRO Australia Telescope National Facility.
ATCA is a radio telescope, an interferometer comprising 6×22m dish antennas. Five of these are on a 3km long E-W track with the sixth antenna a further 3km away. Five antennas can be placed at different locations along the track to vary the baselines between all the antennas. An advantage of radio telescopes is that separate antennas can be linked together electronically to simulate a telescope equal in size to the maximum baseline distance. This increases the resolution of the telescope, that is the ability to see fine detail. Having multiple antennas provides great collecting area, hence higher sensitivity, than just two antennas. It also improves what radio astronomers call u-v coverage. Over a long observing run, typically 12 hours, the signals from each antenna can be correlated to from an image in a process known as Earth-rotation synthesis.
Every month or so the antennas of ATCA can be reconfigured to new spacings. One or more of the five antennas on the track are driven to a new position then jacked up off the track to mounts. The electrical systems and fibre optics are then reconnected and the telescope is ready for operation with a new configuration. To see what happens in a reconfiguration have a look at this great movie below showing a 1 1/2 hour operation in just over 2 minutes!
The movie was made by one of the ATNF astronomers, Dr Emil Lenc during a recent reconfiguration. It was compiled from 2877 photos taken over 1.5 hours.
