GCN Circular 18481
D. A. Perley (DARK/NBI) and S. B. Cenko (NASA/GSFC) report: The Palomar 60-inch robotic telescope responded automatically to the alert for GRB 151027A (Maselli et al., GCN151027A) and began a sequence of i, r, and z-band imaging at 04:00:49 UT, 145 seconds after the BAT trigger. We identify a very bright afterglow consistent with the UVOT and KAIT (Zheng et al., GCN18479) positions in all filters. The preliminary afterglow light curve shows a slow rise to a peak at about ~5 minutes after the GRB trigger, then slowly fades by about 1 magnitude between then and approximately 30 minutes after the trigger. Over the next 20 minutes it then rapidly rebrightens by about 0.7 magnitude. Little or no fading is seen after that point (through to at least 90 minutes after the trigger.) Continued monitoring is encouraged, and should remain possible even from small telescopes for quite some time. High-resolution spectroscopy is also strongly encouraged.