Long-slit Intermediate Resolution InfraredSpectrograph for the WHT
Instrument Features
Focal Station Cassegrain
Wavelength range 0.9 - 2.4 microns
Optimization Entire wavelength range
Array format Rockwell Hawaii 1024x1024 HgCdTe
Scales at detector 0.25 arcsec / pixel
Main observing modes Imaging and Long-slit Spectroscopy
Other observing modes Multi-object spectroscopy, coronography with apodization masking and Polarimetry
Detector temperature 71 K
Imaging mode
FOV 4.2' x 4.2'
Sensitivity K=22.13, H=23.68, J=24.75, Z=25.24 for t=1hr, S/N=3 in 0"5 aperture
Spectroscopy mode
Slit Length 4.2' 
Slit Widths  0.75", 1"and 5" 
Spectral resolution Low / medium resolution: R~1000 / 2500 for slit width 0.5" (4 grisms) 
Spectral coverage and Sensitivity*
Bands Z and J (0.887 - 1.531 m m). Limiting magnitudes J=21.3, Z=22.0
Bands H and K ( 1.388 - 2.419 m m). Limiting magnitudes K=18.6, H=19.9
R=2500 (not yet available)
Bands Z ( 0.997 to 1.185 m m). Limiting magnitude Z=21.2
Bands J ( 1.178 to 1.403 m m). Limiting magnitude J=20.3
Bands H ( 1.451 to 1.733 m m ). Limiting magnitude H=19.5
Bands K ( 2.005 to 2.371 m m ). Limiting magnitude K=18.0
* In all cases for the continuum and t=1hr, S/N=3, FWHM=0.5" .
OH supression In software
Multi-object Spectroscopy mode
Number of masks ~8 multislit masks available.

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Last modified: 08/03/02

Page mantained by: Jose Acosta and Mary Barreto