1997). Line-by-line images have been inspected for spurious features which have been identified and removed.

 The optical photometry
-----------------------

Optical photometry was conducted in the period October 18–23 1995 at the SAAO 0.75m telescope and UCT Photometer employing a Hamamatsu R93402 GaAs photomultiplier. BVRI (Cousins) photometry was carried out on the first three nights performing symmetric modules with integration times of 30s or 20s respectively for the B and I, or V and R filters. The typical time resolution for the sequence of all four filters was $\sim$120s, with interruption every $\sim$ 10min for sky measurements. The times and durations of individual runs are reported in Table1. The orbital period has not been fully sampled.

Additional fast photometry in white light has been carried out on October 21 and 23, 1995 using the same photometer, but employing a second channel photomultiplier for monitoring of a nearby comparison star. Continuous 5s integrations were obtained, with occasional interruptions (every 15–20min) for sky measurements (lasting $\sim$ 20–30s). During the two nights, the observations were carried out for 4.3h and 2.5h respectively.

The photometric data have been reduced in a standard manner with sky subtraction, extinction correction and transformation to the standard Cousins system 