3D - THE NEXT-GENERATION NEAR-INFRARED IMAGING SPECTROMETER

The new MPE near infrared imaging spectrometer 3D represents a new gen eration of astronomical instrumentation. It is based on a 256(2) NICMO S-3 Rockwell array and can simultaneously obtain 256 H- or K-band spec tra at R=1100 or 2100 from a square 16x16 pixel field on the sky. Typi cal pixel scales are 0.3('')/pixel or 0.5('')/pixel. 3D is a combinati on of a novel image slicer and a liquid nitrogen cooled long slit spec trometer. It includes high definition on-axis lens optics, a high effi ciency directly ruled KRS-5 grism as well as a cold closed-loop piezo- driven tilt mirror allowing full spectral sampling. The instrument eff iciency including detector is 15%. Combining the advantages of imaging and spectroscopy increases the observing efficiency on key astronomic al objects (e.g. galactic nuclei) by such a large factor over existing grating or Fabry-Perot spectrometers that subarcsecond near-IR spectr oscopy of faint Seyferts, starbursts, quasars, or distant galaxy clust ers becomes feasible for the first time with 4m-class telescopes. As a portable instrument 3D has already been successfully deployed on seve ral 2 and 4m-class telescopes.