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KSPEC is a cross-dispersed spectrograph designed to cover the atmospheric windows from 1--2.5 $\mu$m in one spectral frame on a 256$\times$256 pixel NICMOS-3 HgCdTe detector array at the f/31 focus of the UH 2.2m telescope. The entire spectral range is covered in a single frame; therefore the instrument uses a fixed grating and cross- dispersing prism with no filters or other moving components. This results in a simple mechanical and optical design, and in a high-throughput instrument that is easy to use.
The spectrograph provides medium ($\lambda / \Delta\lambda \sim$ 700) spectral resolution for classification work, emission line detection, and redshift measurements. The instrument uses a second NICMOS-3 array for slit-viewing. This facilitates the acquisition of optically invisible objects, documents the slit position, and aids in position control during the spectroscopic observations. The slit size is 0.6$\times$7 arcsec; the slit-viewing detector has a field-of-view of $\sim$ 1 square arcminute. A second spectroscopic configuration (not cross-dispersed) uses a K-band order-sorting filter to provide a 0.6$\times$25 arcsec slit for the 2--2.35 $\mu$m wavelength range only.
