Telescope mount

The telescope is mounted to the gondola frame on the elevation (pitch) axis drive shaft. It can pivot around this axis by a torque motor that connects the gondola frame to the telescope mount. During launch and landing, the telescope is stowed upright, protected by the frame. The gondola will turn in azimuth (yaw) by means of a reaction-wheel mounted on top of the gondola. The wheel is part of the Momentum Transfer Unit (MTU).

In order to isolate the high frequency gondola jitter from the telescope we have developed a new mount equipped with a passive stabilizing system, which is basically composed of a spring, a mass, and a damper. The figure above shows a schematic of the mount. Two cages are connected together via flex-pivot spring supports. The outer cage is directly attached to the elevation motor shaft and spins around the elevation axis. The telescope itself is connected to the inner cage also by means of two flex-pivots that allow the telescope to rotate orthogonally to the elevation spin axis. Flex-pivots are weak torsional springs but they are capable of sustaining strong transversal and longitudinal forces. The spring-mass oscillation is passively damped with eddy currents: copper conductors move between strong permanent magnets and the interaction between the electrons in the conductor and the external magnetic field generates a force in the direction opposite to the velocity of the conductor. This new mount will allow stable pointing of the telescope, down to sub arcsec levels, even if the gondola is experiencing high frequency jitter of the order of several arc seconds.