PHARO: A Near‐Infrared Camera for the Palomar Adaptive Optics System

Abstract
We describe Cornell's near‐infrared camera system PHARO (Palomar High Angular Resolution Observer) built for use with the JPL Palomar Adaptive Optics System on the 5 m Hale telescope. PHARO uses a 1024 × 1024 HgCdTe HAWAII detector for observations between 1 and 2.5 μm wavelength. An all‐reflecting optical system provides diffraction‐limited images at two scales, 25 and 40 mas pixel−1, plus a pupil imaging mode. PHARO also has a coronagraphic imaging capability and a long‐slit grism spectroscopy mode at resolving power ≈1500. The instrument has been in use with the AO system at Palomar since early 1998.