TITLE: GCN GRB OBSERVATION REPORT NUMBER: 825 SUBJECT: GRB 000926: optical observations DATE: 00/10/01 01:16:56 GMT FROM: Johan U. Fynbo at ESO,Garching J. P. U. Fynbo, P. Moller (ESO), J. Gorosabel (DSRI, Copenhagen) J. Hjorth, B. L. Jensen, and H. Pedersen (U. of Copenhagen), report on behalf of a larger European GRB Collaboration: "Using the ALFOSC on the 2.5m Nordic Optical Telescope, we have obtained further R-band imaging of the Optical Transient (OT) of GRB 000926 (GCN #801, #803, #804) on 2000 September 30.83 UT. We also report the results of B-band imaging on 2000 September UT 27.88 - 30.85. We find the following magnitudes of the OT using R=17.06 and B=18.50 for the reference star of Halpern et al. (GCN #806, #824) : UT -------------------------- 30.83 R=22.45+-0.05 27.89 B=20.41+-0.03 29.86 B=22.83+-0.08 30.85 B=23.46+-0.10 We note that the colour of the OT, B-R=0.95+-0.05 (Halpern et al., GCN #824), is similar to that of the OT of GRB 000301C at z=2.04, B-R=0.91+-0.03 (Jensen et al., astro-ph/0005609). The estimated intrinsic extinction for this OT was in the range A(V)=0.11-0.35."