Observations

All observations were obtained at the 0.6-m telescope of the Instituto Astronômico e Geofísico, University of São Paulo, at the Pico dos Dias Observatory of the Laboratório Nacional de Astrofísica, Brazil. Light curves were observed in five nights in August 1997. A 8#8 filter was used throughout in order to inhibit the contamination of the measurements by the strongest nebular emission lines (in particular H-alpha). Moreover this facilitates a comparison with the results of GB83 who have also observed most of their light curves in B. The integration time was 90^s, with a dead time of 8^s between integrations. A back-illuminated EEV CCD was used as detector. A journal of the observations is given in Table 1.

Table 1: Journal of observations of MT Ser

	HJD
Date	(2450000+)	N*
1997 Aug 22	683.403 - .589	144
1997 Aug 23	684.488 - .562	65
1997 Aug 25	686.401 - .580	153
1997 Aug 26	687.400 - .575	154
1997 Aug 27	688.405 - .573	148

^*Number of integrations