TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3767 SUBJECT: GRB050805a: MASTER optical candidat DATE: 05/08/05 20:48:55 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, Krushinski V. Sternberg Astronomical Institute, Moscow Union "Optic" MASTER (http://observ.pereplet.ru) responded to GRB 050801 (Swift trigger 149118). The first image was 35 sec after Notice Time and 113 sec after SWIFT probable GRB050805 detection (19:14:00.34 UT, GCN3766) under the evening sky near the horizont. The first image was saturated. The first not saturated image was at 720 sec after GRB time (exposition 1 s). Optical limit is about 12.5 (unfiltred close to R). On next images we see new variable faint source 14.5 inside Swift error box wich disapear after . alpha = 22 04 40.91 delta = +29 51 48.1 error is about 2''. The JPG-images are available at http://observ.pereplet.ru/images/GRB050805/1.jpg . This work is supported by RFFI 04-02-16411 grant. This message can be cited. Mailto: lipunov@sai.msu.ru