CIRPASS is a near-infrared, medium resolution (R~3000) integral field unit spectrograph operating over the wavelength range 1.0-1.67um with good sensitivity. We have negotiated its use for semester 2003A as a visitor instrument on Gemini South.
CIRPASS features an integral field unit (IFU) and a fiber-fed NIR spectrograph. The instrument provides 2D IR (J and H) spectroscopy in two different formats (~10 x 5 arcsec; see IFU configurations). The telescope beam goes through a changeable fore-optics which feed 490 hexagonal doublet lenses attached to fibers. The hexagonal lenses provide an area filling factor of 100% and project onto the sky in an elliptical arrangement.
A 400 l/mm grating provides 200nm wavelength coverage at about 0.44nm resolution (2 pixel per resolution element; resolving power R=3200) with the 1024x1024 array.
As a visitor instrument, CIRPASS does not contain an on-instrument wavefront sensor and therefore guide stars, which are mandatory for all observations with Gemini, will need to be acquired using the facility peripheral wavefront sensor(s).
Last update 26 August 2002; Phil Puxley