PRIMA Star Separators Françoise Delplancke, Frédéric Derie TNO-TPD team (Jan Niejenhuis)

Specifications UT and AT 2’ diameter FoV, unlimited access 2x 2” sub-fields 80 mm output beams Symmetry –Full symmetry for the ATs, including w.r.t. light ducts –Inherent slight dissymmetry for the UTs Integrated metrology end-point (AT) Independent control of image and pupil positions at 10 Hz Chopping in pupil plane Pupil relay No OPD introduced when tracking No transmissive element (10µm) High eigen-frequencies

STS for the ATs: constraints Very limited volume (cylinder of ø ~1m) Low thermal dissipation Good thermal stability (0 to 15ºC) Complex interface with the AT: –Has to mimic the current one (electrical/mechanical I/F) –Has to be transparent for the current software –Exchange of single-feed / dual-feed ROS has to be: Simple (limited manned operation) Reproducible (within 0.1mm / 1’) Without need of a significative STS realignment (automatic alignment check and correction is foreseen)

STS for the ATs: concept (1)

STS for the ATs: concept (2)

STS for the UTs: constraints No derotator but full sky coverage Mechanical interface –with existing supporting towers –without affecting MACAO Possibility of using the currently installed single-feed facility –without affecting the alignment –with a minimum of manned operations Adapted to alignment tools As similar as possible to the STS-AT concept

STS for the UTs: concept (1)

STS for UTs: concept (2)

Tip-tilt mechanisms In pupil / in focal plane Rotation around vertex => no OPD introduced Hinge mechanism Fast response time: –100Hz first eigenfrequency –10ms to send command (could be improved if needed) –10ms to reach position –=> 50Hz actuation frequency

Mechanism performances