|11th of September 2017|
|The Parkes Master Equatorial|
|(by Tim Wilson)|
When consideration was being given to the design of the Parkes radio-telescope
in the 1950s, British inventor-engineer Barnes Wallis was consulted.
Over lunch with Taffy Bowen, Wallis asked how the telescope would be driven,
and Bowen replied that the plan was to use the conventional method of using a
small equatorial telescope built next to the radio telescope. Bowen recounts,
"It took him about thirty seconds -- certainly no more than a minute. He
pointed a finger at me and said `You're wrong. The place to put the equatorial
unit is at the intersection of the two axes of rotation [elevation and azimuth]. You derive
an error signal and servo this back to the main telescope. It's perfectly obvious
that's the way to do it'."
Wallis later patented the idea, and the Parkes telescope became the first of a number of large radio-telescopes to adopt it. The Master Equatorial unit was manufactured by the German company Askania, and the image above, dating from 1960, shows adjustments being made to the ME after installation.