TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2262 SUBJECT: MASTER: optical observation GRB030601 DATE: 03/06/01 22:25:04 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, A.Krylov, V.Kornilov, G.Borisov, D.Kuvshinov, A.Belinski, I.Chilingarian, M.Kuznetsov, S.Potanin, V.Vitrischak, G.Antipov Sternberg Astronomical Institute, Alexsandr Krylov Observatory, Moscow After GRB030601 alert (HETE 2728) MASTER robotic telescope (http://observ.pereplet.ru) had automatically pointed to the corresponding area of the sky (105 seconds after trigger time). There were clouds near the horizont and they were imaged on the CCD frame. First measurable image of the error box area was taken 55 minutes after the burst. No optical counterpart was visible up to 12th magnitude in R band. We had been observing about 90% of the error box area for almost 3 hours. On the last image taken on 21:26UT (3h13m after the burst) no optical counterpart is visible up to 15th magnitude in R band. We had to stop our observations because of rain with possible thunderstorm. Observations were made under bad weather conditions (clouds + low altitude above the horizont, 25 degrees at culmination + bright sky because of high Moscow's latitude). These are preliminary results. This message may be cited.