VISIR: a mid-infrared imager and spectrometer for the VLT

摘要

Abstract: In 1992, the European Southern Observatory (ESO)committed a phase A study of a mid- infrared instrumentfor the 2nd unit VLT telescope, to a consortium oflaboratories (SAp at Saclay, France; SRON at Groningen,Germany; and the Kapteyn Observatory at Roden,Netherlands). The results of the study are presented.One key scientific objective for this instrument isforeseen to be the study of dust. The requiredobserving modes are (1) diffraction limited imagingboth at 10 and 20 microns, and (2) spectroscopy at lowresolution (R $APEQ 500) both at 10 and 20 microns.Another key domain is the study of atomic, molecular,and ionic lines observable in the atmospheric window at10 and 20 microns. Given the various environments wherethe lines originate, medium ($APEQ 5000) to high ($APEQ30,000) spectral resolution is needed. The opticaldesign, as well as a mechanical layout, incorporatingthe various modes is described. The imaging andspectroscopic channels are separated. The spectrometeris based on a long slit all reflective design. Twooptical configurations have been studied in detail.Because of the need for variable magnifications, theimager is based on refractive optics. !9