Optical telescope fibre positioning devices
A positioning system comprising a mounting assembly arranged to move a positioning device via a magnetic coupling interaction between the mounting assembly and the positioning device. The positioning device is configured to limit the spread of flux away from the device.
1. An optical telescope fibre positioning system, comprising:
a mounting assembly including a piezo electric actuator and at least one electrode for applying an electric potential to the piezo electric actuator, the electric potential distorting the actuator; and
a positioning device for positioning an optical fibre, the positioning device being magnetically coupled to the mounting assembly, the positioning system is configured to limit the spread of magnetic flux; wherein application of electric potential to the piezo electric actuator generates distortion of the piezo electric actuator which produces movement of the positioning device via the magnetic coupling.
2. The optical telescope fibre positioning system of claim 1 wherein the mounting assembly further includes a magnetic flux guide including a magnet, the magnetic flux guide being configured to guide the magnetic flux between the magnet and the positioning device.
3. The optical telescope fibre positioning system of claim 2 , wherein the magnetic flux guide is of ferrous material.
4. The optical telescope fibre positing system of claim 1 wherein the magnetic flux guide is cup shaped.
5. The optical telescope fibre positioning system of claim 1 wherein, in use, the magnetic flux guide is in contact with the positioning device.
6. The optical telescope fibre positioning system of claim 1 wherein the mounting assembly further includes a support structure for contacting the positioning device.
7. The optical telescope fibre positioning system of claim 6 wherein the support structure is a jewel bearing.
8. The optical telescope fibre positioning system of claim 6 wherein the support structure includes multiple contact elements.
9. The optical telescope fibre positioning system of claim 1 , further comprising an optical fibre support tube, the positioning device being moved at regular time intervals and wherein the frequency of movement of the positioning device matches a resonant frequency of optical fibre support tube.
10. A sensor array for an optical telescope comprising a plurality of the optical telescope fibre positioning systems of claim 1 wherein the positioning devices are configured adjacent to one another and the magnetic flux of each device is limited to limit interference with adjacent devices.
11. A tube for supporting an optical fibre in the optical telescope fibre positioning system of claim 1 , wherein the tube is comprised of a pultruded carbon fibre tube.
12. The tube according to claim 11 wherein the pultruded carbon fibre has high modulus.
13. The optical telescope fibre optic positioning system of claim 1 , the system being configured such that the piezo electric actuator returns to an undistorted configuration on removal of the electric potential.
14. The optical telescope fibre optic positioning system of claim 13 , wherein the positioning device is configured to slip with respect to the mounting assembly upon removal of the electric potential to retain the position of the positioning device.