Hexapod-Telescope

The Hexapod-Telescope (HPT) was a Ritchey-Chrétien optical telescope, that operated in 2006-2017 in the Cerro Armazones Observatory (OCA) in northern Chile, and is currently decommissioned.

The notable feature of the HPT – and the reason for its name – was the design of its mount. Instead of the typical mounting where the telescope moves on two rotating axes, the mirror cell was supported by six extensible (variable-length) struts, an arrangement known as a Stewart platform. This configuration allowed the telescope to move in all six spatial degrees of freedom and provided strong structural integrity. Furthermore, the six-leg structure allowed for a very precise positioning and repeatability. The HPT could have been rotated ±45° around the optical axis in any position. The mount allowed observations up to 30° elevation. Additionally, by using carbon fiber composites, the HPT was lighter by a factor of ten than classical telescopes of the same aperture. As a result, the ratio of bearing pressure and its own weight was very high. The active primary mirror had a diameter of 1.5 meters and – with a thickness of only 50 mm – was mounted on 36 piezo actuators. The secondary mirror was also supported by a motorised adjustable hexapod.