TITLE: GCN GRB OBSERVATION REPORT NUMBER: 967 SUBJECT: GRB010222, optical observations DATE: 01/02/22 21:04:26 GMT FROM: Arne A. Henden at USNO/USRA A. Henden (USRA/USNO) and F. Vrba (USNO), on behalf of the USNO GRB team and a larger European GRB collaboration, report: We observed the BeppoSAX error box for GRB010222 (GCN 959, 960, 966) with the USNOFS 1.0-m telescope under cloudy conditions. The discovery of the optical transient for this burst was given in Henden (GCN 961, 962). The final astrometry for the OT, relative to USNO-A2.0, is 223.05229 43.01840 14:52:12.55 +43:01:06.2 (J2000) with internal errors of 0.2arcsec. This is in agreement with the values given in McDowell et al. (GCN 963). A finding chart (R-band, 4.5x4.5arcmin, NE=upperleft) is given at ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb010222r.jpg BVRcIc frames were taken shortly after the localization posting. However, only the preliminary R-band measures are reported here. The quality of the photometry suffered due to the thick clouds, but is good enough to show definite fading of the transient: UT exp Rc err 010222.486 1x300 18.36 0.059 010222.510 2x300 18.52 0.054 010222.518 2x600 18.68 0.059 010222.533 2x600 18.67 0.057 Where the R-band magnitudes are relative to the bright USNO-A2.0 star (identified as "A" on the finding chart) at J2000 coordinates 14:52:14.80 +43:01:40.9 and that has an assumed magnitude R=14.70. More careful all-sky calibration of this field will be performed on the next few nights. The intent is to only calibrate in BVRcIc; please contact Henden if you need U-band calibration as well.