TITLE:   GCN CIRCULAR
NUMBER:  9916
SUBJECT: GRB 090902B: Skynet/PROMPT Observations
DATE:    09/09/16 20:05:51 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, K. Ivarsen, A. LaCluyze, A. Foster, J. Moore, A. 
Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander 
report:

Skynet observed the Fermi/LAT localization of GRB 090902B (de Palma et al., 
GCN 9867) with four of the 16" PROMPT telescopes at CTIO beginning 13.3 
hours after the trigger in BVRI through variable cloud cover.

We do not detect the afterglow (Kennea et al., GCN 9868; Swenson & Siegel, 
GCN 9869).  Stacking only images that increase the limiting magnitude 
yields:

mean                                                       1-sig.   1-sig.
time                                3-sig.                 sys.     stat.
since                               lim.     cal.          cal.     cal.
trig.   tel.       exp.      fil.   mag.     stars         unc.     unc.
(h)                (# x s)                                 (mag)    (mag)

14.4    PROMPT-4   18 x 80   R      19.8     240 USNO B1   0.185    0.001
14.4    PROMPT-3   18 x 80   B      19.0     100 USNO B1   0.296    0.002
14.4    PROMPT-5   18 x 80   I      19.0     278 USNO B1   0.234    0.001
14.4    PROMPT-2   17 x 80   V      19.0     217 NOMAD     0.255    0.001