<title>Hectospec: a 300-optical-fiber spectrograph for the converted MMT</title>

摘要

We describe a multi-object spectrograph that is currently under design for the f/5 focus of the converted Multiple Mirror Telescope. The f/5 Cassegrain focus will use a three element refractive corrector to produce a 1 degree(s) diameter field of view well matched to multi-object spectroscopy with optical fibers. The optical fibers will be mounted on magnetic buttons and positioned with two high speed robots, using the general techniques pioneered by the AUTOFIB instrument. Our goal is to position the 300 fibers in 300 seconds. The spectrograph optics will be bench mounted on the observing floor, and will be fed by fibers that are 10 meters in length. The spectrograph will have a 250 mm diameter collimated beam to allow a resolution of 4 to 8 $angstrom FWHM over approximately an octave of spectrum between 3400 $angstrom and 1 micrometers . It is our intention to complete the Hectospec before the commissioning of the f/5 focus in late 1996.