Tircam: A mid-infrared camera for ground-based astronomy

Abstract

A mid-infrared (8 – 22 µm) camera, equipped with a Hughes hybrid bulk Si:As array detector of 10 × 64 pixels was developed for the 1.5 m Italian Infrared Telescope (TIRGO). The instrument was used for narrow-band 8–14 µm high-background astronomical observations. Here we present a short description of the camera, including its fast readout electronics and its optical design. When used at TIRGO, the camera has a pixel scale of 1.23 arcsec/pix. From the observations of infrared standard stars we derived a noise equivalent flux density (NEFD) that, for all the filters, is in the range 0.5–0.7 Jy × arcsec⁻² xmin^−1/2 and a point spread function (PSF) of the order of 3 arcsec(FWHM). Mosaics of the extended sources Mars at 8.8, 9.8, and 12.5 µm, and of the star forming region Orion BN-KL Nebula at 12.5 µm, are shown. The camera performances are also illustrated on the basis of the image of the post-AGB source CRL618.