TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3755 SUBJECT: GRB050803: MASTER further analys DATE: 05/08/04 09:45:28 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, V.Kornilov, D.Kuvshinov, N.Tyurina, A.Belinski, E.Gorbovskoy, A.Krylov, G.Borisov, V.Vladimirov Sternberg Astronomical Institute, Moscow Union "Optic" MASTER (http://observ.pereplet.ru) responded to GRB 050801 (Swift trigger 148833, GCN 3752). The first image was at 198 sec after SWIFT GRB050803 detection (19:14:00.34 UT) under the bad weather conditions on the evening sky near the horizont (GCN3750). We have the first low resolution spectra (50A) image of the error box by 200 mm camera up to 9m. The first unfiltred image on 355 mm camera was made at 28 min (19h32m25s UT) after GRB time due to technical problems (the limit is 14.6 m). The magnitude close to R. UT timme GRB Time (min) Exp Optical limit 19:32:25.65 18.4 30 s 14.6 19:49:00.31 35.0 30 s 17.0 19:49 - 20:08 35.0 - 54.0 12x30 s 18.6 The JPG-images are available at http://observ.pereplet.ru/images/GRB050803/all.jpg . Imoprtant note: this is the second night Swift GRB accessible alert during this year at Moscow region. The first alert was in rain. This work is supported by RFFI 04-02-16411 grant. This message can be cited. Mailto: lipunov@sai.msu.ru