TITLE: GCN CIRCULAR NUMBER: 44827 SUBJECT: GRB 260604C: MASTER OT J145749.59+284903.0 optical counterpart discovery DATE: 26/06/04 22:45:21 GMT FROM: Vladimir Lipunov at Lomonosov Moscow State University <lipunov@sai.msu.ru> MASTER OT J145749.59+284903.0 discovery MASTER-Tavrida auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) discovered OT source at (RA, Dec) = 14h 57m 49.59s +28d 49m 03.0s on 2026-06-04.86020 UT. The OT magnitude (unfiltered) is 17.5m at04.86020UT (mlim=19.4). The OT is seen in 14 images. There is no minor planet at this place. We have reference image on 2020-09-17.71399 UT with unfiltered mlim= 18.1m. Spectral observations are required. View this GCN Circular online at https://gcn.nasa.gov/circulars/44827. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...