TITLE: GCN CIRCULAR NUMBER: 9996 SUBJECT: GRB 090926B: Skynet/PROMPT Observations DATE: 09/10/06 04:07:49 GMT FROM: Josh Haislip at U.North Carolina 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 Swift/BAT localization of GRB 090926B (Grupe et al., GCN 9935) with four of the 16" PROMPT telescopes at CTIO beginning 2.7 hours after the trigger in UVRI. We do not detect the afterglow (Grupe et al., GCN 9935; Malesani, Fynbo & D'Elia, GCN 9944). 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) 2.7 PROMPT-4 4 x 80 R 19.9 40 USNO B1 0.424 0.002 2.7 PROMPT-2 4 x 80 V 18.2 11 NOMAD 0.099 0.003 2.7 PROMPT-5 3 x 80 I 18.2 32 USNO B1 0.414 0.003