Adaptive Optics Limits with the Keck Interferometer

  • Sensitivity is lower than single telescope AO due to the dichroic which sends light to the interferometer.
  • Sensitivity somewhat dependent on object color.
  • R < 12 for all V2 modes.
  • R < 10 for NULLING mode.
  • R < 14 for Dual Field Phase Referenced mode (ASTRA-DFPR).
    • See the Keck Observatory AO page for more details.
    • While the AO is locked on a star, light from a nearby offset star may be sent to the interferometer. The maximum offset is about 15 arcsec, but depends on position angle: please contact NExScI for details. The minimum offset is about 0.2 arcsec. A single component of a pair that is closer than that may be selected for interferometer measurements by adjusting the angle tracker (KAT) settings: please refer to the KAT section. Offset guiding may result in decreased observing efficiency. Offset guiding is NOT available for the NULLING mode.
    • The image rotators are used in vertical angle mode.

    Return to KI Sensitivities page
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