The discovery of an optical counterpart to GRB010222 ( detected by BeppoSAX ; Piro 28 ) was announced 4.4 hrs after the burst by Henden ( 16 ) .
The Sloan Digital Sky Survey ’ s 0.5m photometric telescope ( PT ) and 2.5m survey telescope were used to observe the afterglow of GRB010222 starting 4.8 hours after the GRB .
The 0.5m PT observed the afterglow in five , 300 sec g ^ { * } band exposures over the course of half an hour , measuring a temporal decay rate in this short period of F _ { \nu } \propto t ^ { -1.0 \pm 0.5 } .
The 2.5m camera imaged the counterpart nearly simultaneously in five filters ( u ^ { * } g ^ { * } r ^ { * } i ^ { * } z ^ { * } ) , with r ^ { * } ~ { } = ~ { } 18.74 \pm 0.02 at 12:10 UT .
These multicolor observations , corrected for reddening and the afterglow ’ s temporal decay , are well fit by the power-law F _ { \nu } \propto \nu ^ { -0.90 \pm 0.03 } with the exception of the u ^ { * } band UV flux which is 20 % below this slope .
We examine possible interpretations of this spectral shape , including source extinction in a star forming region .