High-resolution spectrograph with R4 echelle for LAMOST

A preliminary design study for a high-resolution echelle spectrograph to be used for LAMOST (The large Sky Area Multi-Object Fiber Spectroscopic Telescope) that is currently under construction is presented. In order to obtain a resolution-slit product of about 40000 as required by science case, the less expensive design used a 105mm beam feeding a 408mm deep Echelle is good solution. The optical design of high resolution Echelle spectrograph for LAMOST is given. This spectrograph will be more powerful tool for astrophysical research using high-resolution spectroscopy in China. Some new technology and novel design concepts have been adopted in this spectrograph, such as white pupil collimator system, R4 Echelle with large blaze angle, and the fold and off-axial Schimidt camera without center obstruction and so on.