Four Oke-Gunn (OG) standards, HD 19445, HD 84937, BD+26 2606 and BD+17 4708 are used as standard stars for flux calibration in the BATC project. They are also w
A brief description of the NAO coude echelle spectrograph mounted on the 2.16m telescope at Xinglong station is given. This echelle spectrograph is located at t