TITLE: GCN GRB OBSERVATION REPORT NUMBER: 227 SUBJECT: "GRB 990123: New BV Observations" DATE: 99/01/26 02:30:05 GMT FROM: Ram Sagar at UPSO R.Sagar, A.K. Pandey, R.K.S. Yadav, Nilakshi and V. Mohan of U.P. State Observatory, Manora Peak, Nainital, India report: "We have observed the optical transient (GCN #201) of GRB 990123 (GCN #199) with the 104-cm telescope of the U.P. State Observatory, Manora Peak, Nainital, India in Johnson B and Cousin R photometric passband under good photometric sky conditions. We have calibrated the images using photometric standards located in the field of open star cluster M67. In each filter three images of 20 minutes are obtained and they are stcked to improve signal to noise ratio of the optical transient. We obtain the following magnitudes: UT date filter mag err Jan 24.90 R 21.25 0.1 Jan 24.99 B 22.05 0.2 The (B-R) colour of the OT becomes redder by about 0.2 mag compared to our observations on Jan 23, 1999 (GCN #218).These results are preliminary and more accurate results will be published later. At the Web site http://www.rri.res.in/grb990123/ all the images taken on the nights of Jan 23 and 24 are available. We have also taken images during the night of 25/26 Jan 99 and will report the results later. Sky conditions were good for photometric observations on the nights of 24/25 Jan 99 and 25/26 Jan 99 and we have observed the M67 field for calibration purposes. Precise determination of the BVRI magnitudes of the stars as well as of the OT in the field of the GRB990123 are in progress. This message may be cited."