TITLE: GCN CIRCULAR NUMBER: 20506 SUBJECT: LIGO/Virgo G270580: A third optical transient from CNEOST DATE: 17/01/23 01:28:55 GMT FROM: Jinzhong Liu at Xinjiang Astronomical Observatory Haibin Zhao (PMO/CAS), Dong Xu (NAO/CAS), Bin Li, Getu Zhaori, Hao Lu (PMO/CAS), Hanjie Tan (CCU), Zhijian Xu, Wenxiong Li, Zesheng Yang, Xiaofeng Wang (THU), Lifan Wang (PMO/CAS), Jujia Zhang (YNAO/CAS), Hao Song (THU), Jinzhong Liu, Hubiao Niu, Yu Zhang, Xuan Zhang, Guangxin Pu, Shuguo Ma, Taozhi Yang, Fangfang Song (XAO/CAS), Tianmeng Zhang, Xu Zhou (NAO/CAS), Jirong Mao, Jinming Bai (YNAO/CAS), Huanxue Feng, Zipei Zhu (NAO/CAS) report on behalf of the Gravitational Wave Follow-Up Network by NAO-PMO-XAO-YNAO in China (GWFUNC): Further analysis of the CNEOST observational data reported in our previous GCN 20497 reveals a third optical transient, dubbed as PTSS-17dgm, at coordinates R.A. (J2000) = 09:30:36.58 Dec. (J2000) = +21:24:42.32 with m(r) = 18.94 +/- 0.08 at 18:24:25 UT on 2017-01-21. Again this object may be a newly exploded supernova. -- N: Jinzhong Liu, Dr. O: Main building, 213 P: 150, Science 1-Street, Urumqi, Xinjiang 830011, China T: 86 991 3689027 D: 2012-07-14 E: optics@xao.ac.cn