TITLE: GCN CIRCULAR NUMBER: 38644 SUBJECT: Fermi GRB 241221A: Global MASTER-Net observations report DATE: 24/12/21 01:01:56 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, 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. 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 241221A ( Fermi GBM team, GCN 38643) errorbox 243 sec after notice time and 278 sec after trigger time at 2024-12-21 00:27:12 UT, with upper limit up to 17.1 mag. The observations began at zenith distance = 79 deg. The sun altitude is -28.6 deg. The galactic latitude b = -4 deg., longitude l = 177 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2717268 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 309 | 2024-12-21 00:27:12 | MASTER-SAAO | (04h 52m 56.99s , +35d 14m 41.7s) | C | 60 | 17.0 | 388 | 2024-12-21 00:28:32 | MASTER-SAAO | (05h 02m 42.74s , +35d 15m 48.7s) | C | 60 | 16.8 | 467 | 2024-12-21 00:29:51 | MASTER-SAAO | (04h 46m 21.19s , +33d 19m 48.0s) | C | 60 | 16.9 | 546 | 2024-12-21 00:31:10 | MASTER-SAAO | (04h 56m 00.02s , +33d 20m 16.7s) | C | 60 | 16.9 | 626 | 2024-12-21 00:32:30 | MASTER-SAAO | (05h 04m 32.62s , +33d 20m 18.2s) | C | 60 | 16.9 | 803 | 2024-12-21 00:35:26 | MASTER-SAAO | (05h 14m 04.16s , +33d 21m 01.2s) | C | 60 | 17.0 | 882 | 2024-12-21 00:36:46 | MASTER-SAAO | (05h 09m 48.39s , +29d 32m 59.8s) | C | 60 | 17.1 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/38644. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...