TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  976
SUBJECT: GRB 010222:  Optical Observations
DATE:    01/02/23 07:18:51 GMT
FROM:    Jerome A. Orosz at Astro. Inst, Utrecht U.  <J.A.Orosz@astro.uu.nl>

Jerome A. Orosz, Utrecht University, The Netherlands, reports:

I have observed the field of GRB010222 (GCN 959,960) with the 1 meter
Jacobus Kapteyn Telescope on La Palma.  The conditions were nearly
photometric (very thin cirrus moved in at the last minute) and the seeing
was 1.2 arcseconds.  The preliminary magnitudes given are with respect to
star 'A' in Stanek et al.'s finding chart (GCN 970):

UT start        Filter  exptime     airmass     delta_mag
on Feb 23

06:16:28.0         R     600.0      1.037762    2.95 +/- 0.06
06:27:43.0         V     600.0      1.043099    2.83 +/- 0.07
06:38:45.0         I     600.0      1.050021    2.66 +/- 0.13
06:49:46.0         R     600.0      1.058645    2.82 +/- 0.15

Thus assuming star A has R=17, then the OT had R = 19.95 +/- 0.06
on UT 23.2614.

I have observed several Landolt fields that can be used to approximately
calibrate the field after the fact.  These images and the GRB images are
available upon request.

This message can be cited.