TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1338 SUBJECT: GRB020406(?), optical observations DATE: 02/04/07 22:25:26 GMT FROM: Arne A. Henden at USNO/USRA D. Durig (ddurig@sewanee.edu) and A. McDermott report on behalf of the International AAVSO GRB Network: We observed the RXTE/ASM error box for the short X-ray transient 020406 (Smith et al. GCN 1332), that may be related to a GRB, with the Cordell-Lorenz Observatory 0.3m telescope and ST-9E/AO-7 CCD system. The western half of the error box was mosaiced with limiting magnitude approximately 20. Near the center of the error box an object was found that does not appear on either the blue or red POSS-II plate. At coordinates: 19:00:42.10 +01:27:22.4 J2000 +/- 0.2s +/- 0.4" this object had an estimated unfiltered magnitude of 18.9 (USNO-A2.0 red) on a 10-minute exposure with midpoint UTD 020407.394 (13hrs after the ASM detection); two subsequent exposures showed fading behavior (19.2 and 19.3mag), but a constant brightness also fits within the photometric errors. No known GCVS variable star nor known asteroid is near this position. As this is a crowded field with no obvious galaxies on the POSS plates, this object may just be an unrelated galactic variable of large amplitude.