TITLE: GCN GRB OBSERVATION REPORT NUMBER: 336 SUBJECT: optical observation of the X-ray/GRB transient SAX J0835.9+5118 DATE: 99/05/21 00:01:04 GMT FROM: Alberto Castro-Tirado at LAEFF-INTA Optical report: observation of the SAX J0835.9+5118 field A. Castro-Tirado (LAEFF-INTA Madrid and IAA-CSIC Granada), J. Greiner (AIP Potsdam), S. Phleps (MPIA Heidelberg), E. Pian (ITESRE Bologna) and E. Costa (IAS Frascati) report on behalf of a larger collaboration: "We have obtained two 20-minute R-band exposures of the 1SAX J0835.9 +5118 error box (Gandolfi et al. IAUC 7174) starting at 19:18 UT 20 May 1999 (17.25 hours after the trigger) with the 2.2 m telescope at the German-Spanish Calar Alto Observatory (CAHA). After a visual comparison with the the Digital Sky Survey, no new sources were seen to the DSS-2 limit. At the position of the radiosource reported by Frail et al. (GCN 334) we see a point-like, faint object which is also present in the DSS-2, as pointed out by Bloom et al. (GCN 335). This object does not seem to have changed significantly in brightness. Our frames reach significantly deeper than the DSS-2 image. If the above-mentioned radiosource is not the counterpart to the SAX source, a more detailed analysis and comparison with deeper images in the next few days might yield a counterpart."