  Until recently the positions of gamma ray bursts were not sufficiently well
known within a short timescale to localize and identify them with known
celestial sources. Following the historical detection of the X-ray afterglow of
the burst GRB970228, extending from 30 s to 3 days after the main peak, by the
Beppo-SAX satellite and that of an optical transient 21 hr after the burst, we
report here the detection of the same optical transient, in images obtained
only 16 hours after the burst.
