TITLE: GCN GRB OBSERVATION REPORT NUMBER: 395 SUBJECT: GRB 990806, Optical Observations DATE: 99/08/07 23:03:52 GMT FROM: Jonathan Kemp at Biosphere2 Center & Columbia U J. Kemp, N. Mirabal, J. Halpern (Columbia), J. Parker (SwRI), D. Harkavy (Harvard), E. Costa, & L. Piro (IAS/CNR, Frascati) report on behalf of the BeppoSAX team and the MDM Observatory GRB follow-up team's southern extension: "We imaged the BeppoSAX WFC error circle of GRB 990806 (Piro GCN 392) starting on Aug. 7.19 UT using the CTIO 4m and 0.9m telescopes. In a 5 minute V-band exposure on the 4m, no new object brighter than the limit of the various sky survey plates is seen. The same is true of a series of ten 10 minute R-band images obtained on the 0.9m between Aug. 7.21 and 7.42 UT. No variable object is seen. The 5-sigma limiting magnitude of the summed R-band image is 23.0. Photometric calibration was obtained using the Landolt standard field of PG 2213-006. For possible future reference, we give recalibrated magnitudes of several stars from the USNO-A2.0 catalog: Star RA(2000) Dec(2000) R(USNO) R(CTIO) ----------------------------------------------------- A 03 10 19.577 -68 09 52.08 16.7 16.83 B 03 10 21.996 -68 05 31.11 16.1 16.09 C 03 10 32.916 -68 04 17.54 16.8 17.07 D 03 10 37.871 -68 07 44.91 17.0 17.15 E 03 10 41.537 -68 06 19.68 16.6 16.50 F 03 10 52.539 -68 06 30.05 15.7 15.58 G 03 10 57.979 -68 05 01.92 16.2 16.33 ----------------------------------------------------- A finding chart for these stars and a CCD image are posted at http://www.astro.bio2.edu/grb/ This message may be cited." [GCN OPS NOTE (07Aug99): There was a typo in the original URL. The URL in this archive copy of the Circular has been corrected at the author's request.]