The University of Hawaii 2.2 meter fast tip-tilt secondary system

Using a new f/31 secondary on a tip-tilt platform, we have built an image-s tabilization system which has been used regularly for astronomical imaging and spectroscopy on the University of Hawaii 2.2 m telescope. Diffraction-l inited cores of stellar point-spread functions are achieved in near-infrare d imaging, with Strehl ratios as high as 0.47. K-band images with 0."3 FWHM resolution (without deconvolution) are routinely obtained. The constructio n, operation, and capability of the current system are described, a summary of recent scientific findings is presented, and future improvements are ou tlined.