PHARO: A near-infrared camera for the Palomar Adaptive Optics System

We describe Cornell's near- infrared camera system PHARO (Palomar High Angu lar Resolution Observer) built for use with the JPL Palomar Adaptive Optics System on the 5 m Hale telescope. PHARO uses a 1024 x 1024 HgCdTe HAWAII d etector for observations between 1 and 2.5 mum wavelength. An all- reflecti ng optical system provides diffraction- limited images at two scales, 25 an d 40 mas pixel(-1), plus a pupil imaging mode. PHARO also has a coronagraph ic imaging capability and a long- slit grism spectroscopy mode at resolving power approximate to 1500. The instrument has been in use with the AO syst em at Palomar since early 1998.