TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3146 SUBJECT: GRB050326: optical limit 33min before GRB DATE: 05/03/26 18:26:51 GMT FROM: Grzegorz Wrochna at Soltan Inst.for Nuclear Studies M.Cwiok, K.Krupska, K.Kwiecinska, L.Mankiewicz, K.Nawrocki, B.Pilecki, L.W.Piotrowski, G.Pojmanski, M.Sokolowski, D.Szczygiel, G.Wrochna, on behalf of "Pi of the Sky / ASAS" collaboration http://grb.fuw.edu.pl The GRB 050326 (GCN 3143) error box was observed by "Pi of the Sky" apparatus at Las Campanas Observatory at 9:20 UT, i.e. 33 min before the GRB. 3 exposures, 10s each, have been taken. No new object has been found within the Swift-BAT error box. The limiting magnitude on 3 coadded frames is 11m (unfiltered).