TITLE: GCN CIRCULAR NUMBER: 45591 SUBJECT: MAXI GRB260916.37: Global MASTER-Net observations report DATE: 26/09/16 09:51:37 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA) V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya..Kechin, V.Senik, A.Chasovnikov, K.Labsina (Lomonosov MSU) D.Buckley (SAAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) A.Sosnovskij (Lomonosov MSU) A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory) L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) R.Rebolo (The Instituto de Astrofisica de Canarias) O.Gress, N.Budnev(ISU) MASTER-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) started inspect of the MAXI GRB260916.37 (trigger No 299299081,01h 10m 41.04s , -26d 15m 07.2s, R=1) errorbox 2813 sec after trigger time at 2026-09-16 09:38:52 UT, with upper limit up to 20.0 mag. Observations started at twilight. The observations began at zenith distance = 46 deg. The sun altitude is -12.5 deg. The galactic latitude b = -85 deg., longitude l = 201 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3505122 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 2844 | 2026-09-16 09:38:52 | MASTER-OAFA | (01h 09m 59.35s , -26d 20m 14.8s) | C | 60 | 19.5 | 2904 | 2026-09-16 09:38:52 | MASTER-OAFA | (01h 09m 59.35s , -26d 20m 14.8s) | C | 180 | 20.0 | Coadd 2909 | 2026-09-16 09:39:58 | MASTER-OAFA | (01h 09m 59.38s , -26d 20m 15.0s) | C | 60 | 19.2 | 2975 | 2026-09-16 09:41:03 | MASTER-OAFA | (01h 09m 59.43s , -26d 20m 15.6s) | C | 60 | 19.2 | 3040 | 2026-09-16 09:42:09 | MASTER-OAFA | (01h 09m 59.46s , -26d 20m 16.0s) | C | 60 | 19.0 | 3100 | 2026-09-16 09:42:09 | MASTER-OAFA | (01h 09m 59.45s , -26d 20m 16.0s) | C | 180 | 19.5 | Coadd 3106 | 2026-09-16 09:43:14 | MASTER-OAFA | (01h 09m 59.49s , -26d 20m 16.3s) | C | 60 | 19.0 | 3172 | 2026-09-16 09:44:20 | MASTER-OAFA | (01h 09m 59.46s , -26d 20m 16.8s) | C | 60 | 18.6 | 3238 | 2026-09-16 09:45:26 | MASTER-OAFA | (01h 09m 59.50s , -26d 20m 17.7s) | C | 60 | 18.6 | 3304 | 2026-09-16 09:46:32 | MASTER-OAFA | (01h 09m 59.55s , -26d 20m 18.1s) | C | 60 | 18.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html