PRIMA Star Separators

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PRIMAStar Separators

• Françoise Delplancke, Frédéric Derie
• TNO-TPD team (Jan Niejenhuis)

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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

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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/mechanica
  l 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)

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STS for the ATs concept (1)
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STS for the ATs concept (2)
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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

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STS for the UTs concept (1)
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STS for UTs concept (2)
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Tip-tilt mechanisms

• In pupil / in focal plane
• Rotation around vertex gt no OPD introduced
• Hinge mechanism
• Fast response time
• 100Hz first eigenfrequency
• 10ms to send command (could be improved if
  needed)
• 10ms to reach position
• gt 50Hz actuation frequency

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Mechanism performances