TITLE: GCN CIRCULAR NUMBER: 21780 SUBJECT: LIGO/Virgo G299232: XSNAOC spectral observation of MASTER OTJ033744.97+723159.0 DATE: 17/08/31 20:24:41 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs Liming Rui (Tsinghua University), Xiaofeng Wang (Tsinghua university), Danfeng Xiang (Tsinghua Univeristy), Han Lin (Tsinghua Unviersity), and Huijuan Wang (NAOC) We obtained an optical spectrum (range 380-870 nm) of MASTER OTJ033744.97+723159.0 (Lipunov et al. GCN 21720, GCN2136), on 2017-08-29.54UT with the 2.16-m telescope at Xinglong Station of National Astronomical Observatories of China (NAOC) on BFOSC (Beijing Faint Object Spectrograph and Camera). The spectrum is consistent with a type IIb supernova a few days before the maximum light, using SN96cb data as the spectral templates.