ADAPTIVE OPTICS IMAGING AT 1-5 MICRONS ON LARGE TELESCOPES - THE COMIC CAMERA FOR ADONIS

A new 1-5 mu m high-resolution camera dedicated to the ESO adaptive op tics system ADONIS has been developed as a collaborative project of Ob servatoire de Paris-Meudon and Observatoire de Grenoble, under ESO con tract. Since this camera has been designed to correctly sample the dif fraction, two focal plate scales are available: 36 mas pixel(-1) for t he 1-2.5 mu m range and 100 mas pixel(-1) for the 3-5 mu m range, yiel ding fields of view of 4.'' 5 x 4.'' 5 and 12.'' 8 x 12.'' 8, respecti vely. Several broadband and narrowband filters are available as well a s two circular variable filters, allowing low spectral resolution (R s imilar to 60-120) imagery between 1.2 and 4.8 mu m. This camera is equ ipped with a 128 x 128 HgCdTe/CCD array detector built by the CEA-LETI -LIR (Grenoble, France). Among its main characteristics, this detector offers a remarkably high storage capacity (more than 10(6) electrons) with a total system readout noise of approximate to 1000 electrons rm s, making it particularly well suited for long integration time imager y in the 3-5 mu m range of the near-infrared domain. The measured dark current is 2000 electrons s(-1) pixel(-1) at the regular operating te mperature of 77 K, allowing long exposure times at short wavelengths ( lambda < 3 mu m), where the performances are readout-noise limited. At longer wavelengths (lambda > 3 mu m), the performances are background -noise limited. We have estimated the ADONIS + COMIC imaging performan ces using a method specially dedicated to high angular resolution came ras.