A dedicated echelle spectrometer for the Anglo-Australian Telescope

Abstract

An echelle spectrometer has been manufactured for use combined with the image photon counting system (IPCS) on the Anglo-Australian Telescope. This instrument employs a collimator/camera lens and in its principal configuration uses broad interference filters to isolate separate echelle orders. Very long multi-slits or multi-image masks can cover large areas of extended sources to obtain profiles of single emission lines, or interstellar absorption lines, from many spatial elements simultaneously. Provision is made for a grism to be inserted to achieve cross-dispersion with a short slit or, when rotated by 90°, produce a simple low dispersion spectrum of the source. Furthermore, the insertion of a plane mirror produces a direct image of the field when a clear area is driven into position to replace the multi-slits. All complex operations are remotely controlled with a BBC microcomputer.