TITLE: GCN CIRCULAR NUMBER: 42059 SUBJECT: Fermi trigger No 781128896: Global MASTER-Net observations report DATE: 25/10/02 20:30:48 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs lipunov@xray.sai.msu.ru

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, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)

MASTER-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB251002.84 (trigger No 781128896,01h 12m 38.40s , -05d 24m 00.0s, R=5.51) errorbox 259 sec after notice time and 291 sec after trigger time at 2025-10-02 20:19:42 UT, with upper limit up to 18.4 mag. The observations began at zenith distance = 50 deg. The sun altitude is -49.8 deg.

The galactic latitude b = -67 deg., longitude l = 138 deg.

Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3005496

We obtain a following upper limits.

Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________

322 | 2025-10-02 20:19:42 | MASTER-Kislovodsk | (00h 53m 34.79s , -05d 12m 04.9s) | P- | 60 | 17.4 | 402 | 2025-10-02 20:19:42 | MASTER-Kislovodsk | (00h 53m 34.79s , -05d 12m 04.8s) | P- | 220 | 18.4 | Coadd 322 | 2025-10-02 20:19:42 | MASTER-Kislovodsk | (00h 53m 50.27s , -05d 35m 28.4s) | P| | 60 | 18.0 | 395 | 2025-10-02 20:20:50 | MASTER-Kislovodsk | (00h 53m 34.79s , -05d 12m 08.8s) | P- | 70 | 18.1 | 395 | 2025-10-02 20:20:50 | MASTER-Kislovodsk | (00h 53m 50.31s , -05d 35m 30.7s) | P| | 70 | 18.0 | 483 | 2025-10-02 20:22:09 | MASTER-Kislovodsk | (00h 53m 34.83s , -05d 12m 10.6s) | P- | 90 | 18.1 | 483 | 2025-10-02 20:22:09 | MASTER-Kislovodsk | (00h 53m 50.43s , -05d 35m 32.0s) | P| | 90 | 18.1 | 592 | 2025-10-02 20:23:47 | MASTER-Kislovodsk | (00h 53m 34.96s , -05d 12m 12.3s) | P- | 110 | 18.4 | 592 | 2025-10-02 20:23:47 | MASTER-Kislovodsk | (00h 53m 50.58s , -05d 35m 34.4s) | P| | 110 | 18.1 |

The observation and reduction will continue. The message may be cited.

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