GCN Circular 668
K. Z. Stanek (CfA), P. M. Garnavich (Notre Dame), P. J. Groot, S. Jha (CfA) and M. Hicks (JPL) report: We have observed most of the RXTE/ASM-IPN error-box of GRB 000508B (GCN 665) using the FLWO 1.2-meter telescope on Mt. Hopkins and the KPNO 2.1m telescope. The center of the GRB 000508B error-box is located at Galactic coordinates (l,b)=(0.48 deg,14.38 deg), and the Schlegel et al. (1998) Galactic reddening toward this direction is E(B-V)=0.51 (A_V=1.7 mag). Due to the proximity to the Galactic plane the stellar field is fairly dense. At KPNO we obtained four 600 sec R-band images, the first two at UT May 10 07:30 and the second two at UT May 10 11:33. At FLWO we obtained two 600 sec R-band images, first one at UT May 10 06:39 and the second one at UT May 10 09:14. In addition, at FLWO we have obtained UBVI images for the field. Using DAOPHOT-II (Stetson 1992) on the FLWO 1.2-meter R-band image we detect about 5,000 objects with R<22.5 in 11x11 arcmin field. Visual comparison with the POSS-II red plate reveals no obvious ``new'' objects. Employing the image subtraction code ISIS-2 (Alard 1999) between the two epochs taken at each telescope reveals four possible variable objects located in the error-box, with the following coordinates and magnitudes from Henden et al. (GCN 667): V1) RA=253.58616 DEC=-20.41683 V=16.75 V2) RA=253.54913 DEC=-20.46479 V=17.33 V3) RA=253.53600 DEC=-20.43531 V=17.72 V4) RA=253.60865 DEC=-20.42111 V=18.24 All of these objects are easily identified on the POSS-II plate, so most likely NONE of these objects is the optical counterpart to GRB 000508B. Further observations are planned at FLWO. This message can be cited.