GCN Circular 10636
Adria C. Updike, Dieter H. Hartmann (Clemson University), and Chris De Pree (Agnes Scott College) report: We observed the field of GRB 100420A (Baumgartner et al., GCN 10628) using the 0.9m SARA telescope located at KPNO beginning 3 hours and 4 minutes after the BAT trigger. We obtained 22 minutes of observations in the R band followed by 20 minutes in the I band at high airmass. At the location of the XRT error circle, we detect no new sources down to a limiting magnitude of R > 19.0, I > 18.5 (as compared to the USNO B1.0 catalog). No further observations are planned.