The Large Sky Area Multi-Object Fibre Spectroscopy Telescope ( LAMOST) Project

Abstract

In astronomy, the physical information content of the optical spectroscopy of celestial bodies is unsurpassed in richness and sophistication. Continuing efforts made by astronomers to obtain more optical spectra have been leading to the major progress in astronomy and astrophysics during this century. However, only small part (about one per ten thousand) of a few thousand millions celestial objects recorded from sky surveys have had their spectra obtained. One of the main reasons is the fact that for a long time one telescope could only do the slit spectroscopic observation for one object at a time (except in the objective-prism spectroscopy when the available dispersion is fairly low), until the technique of multi-object fibre spectroscopy became available in the 1980s. This technique makes use of the optical fibre link to obtain slit spectra of many celestial bodies with one telescope at the same time. Multi-object fibre spectroscopy has been widely used with many existing 4m-class telescopes and as many as 400 spectra can be observed simultaneously. However, the field of view of the existing 4m or larger reflectors is hardly more than one square degree. On the other hand, the conventional Schmidt telescopes have large fields of view of up to several (6–7) degrees, but cannot be made as large as, say 4m in diameter. Considering the more than forty thousand square degrees of the whole sky to be explored and the exponentially increasing number of fainter objects, a new kind of telescope is desperately needed, combining a large field of view (for more objects) and a large clear aperture (for fainter objects).