PRIMAStar 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

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

Mechanism performances