LAMOST Instrument:4000 Fiber Low Resolution Spectroscopy

We present here a design of fiber fed 4000 object low resolution spectroscopy of LAMOS T.And some related problems are discussed briefly. LAMOST is a 4m aperture 5° FOV telescope.4000 object low resolution spectroscopic observation is its main observation mode.The LAMOST inst rument is mainly a multi-object spectroscopy system including 4000 independent fiber positioners, fiber optics, 14 spectrographs and 28 CCD cameras. 4000 fiber is a great challenge to present multi-fiber spectroscopy.And positioning 4000 fiber is one of the two technological difficulties for LAMOST project.