TITLE:   GCN CIRCULAR
NUMBER:  12001
SUBJECT: GRB 110503A: SARA-N Observations and Photometric Calibration
DATE:    11/05/04 17:13:05 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

Adria C. Updike (NASA/GSFC), D. A. Kann (TLS Tautenburg), Dieter H.
Hartmann (Clemson University), and Ken Rumstay (Valdosta State University)
report:

We observed the field of GRB 110503A (M. Stamatikos et al., GCN 11991)
with the SARA-North 0.9m telescope located at KPNO under good conditions
beginning about 13 hours after the trigger and continuing for half an
hour.  We detect the afterglow in each 120 sec exposure.  In a stacked 20
min image with mean time 0.5484375 days after the trigger, we detect the
afterglow at R = 20.20 +/- 0.07 using the SDSS-derived magnitude of the
comparison star given by Kann et al. (GCN 11996).  Further observations
are planned.

The comparison star utilized by Kann et al. has the following SDSS
magnitudes (transformation from Lupton (2005) and Jordi et al. (2006):

u = 21.214
g = 18.546
r = 17.166
i = 16.485
z = 16.111

and Vega magnitudes:

U = 20.431
B = 19.193
V = 17.802
R = 16.819
I = 15.942
Z = 15.562