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NIRI On-Instrument Wavefront Sensor Detector

NIRI is equipped with an on-instrument wavefront sensor (OIWFS) to control flexure and for fast guiding. A HgCdTe detector sensitive to infrared radiation was chosen for the OIWFS to allow NIRI to be used in heavily extincted regions where optical guide stars are not visible. Starlight passes the science pickoff mirrors is used for guidance and to provide tip/tilt information to the telescope control system. The field of view of the OIWFS for each camera can found on the cameras page. Note that the available OIWFS field of view is negligible when using the f/6 camera, and peripheral wavefront sensors are used instead.

Array	HAWAII HgCdTe (Rockwell)
Pixel format	1024x1024 18.5-micron pixels
Spectral Response	1 to 2.5 microns
Dark Current	TBD
Read Noise	TBD
Read Rate/modes	~100 Hz, double correlated reads
Total throughput	J=13% H=20% K=23%
Limiting Magnitude	approximately H~14

Last update May 7, 2003 Joe Jensen