Starbugs are the latest technology in optic fibre positioning – they are tiny, legless, armless robots that tip and totter around on a glass plate to position themselves. These little Bugs can be positioned accurately to within a few microns.
Starbugs are made from coaxial piezo-ceramic tubes, one nestled inside the other, and in the very centre the Bugs carry an optical fibre. Since they are made from a piezoelectric material, when a voltage is applied the tubes bend and flex, making the robots move. The frequency of this vibration movement can be controlled precisely, and computer algorithms are used to tell each robot where to move on the glass plate. When they move, the Starbugs make a loud buzzing noise.
A vacuum state adheres the Starbugs to the glass, so that the telescope can point in any direction without the robots losing grip. The optical fibre in the centre of each Starbug collects light from the telescope’s field of view, and feeds it into a spectrograph. Hundreds of Starbugs can be positioned simultaneously, only taking a few minutes. Starbugs will be used in a future instrument called Hector, a multi-field spectrograph.
Starbugs being tested on a glass plate. Image: Andy Green