The 'outside-in' outburst of HT Cassiopeiae

We present results from photometric observations of the dwarf nova system H T Cas during the eruption of 1995 November. The data include the first two- colour observations of an eclipse on the rise to outburst. They show that d uring the rise to outburst the disc deviates significantly from steady-stat e models, but the inclusion of an inner-disc truncation radius of about 4R( wd) and a 'flared' disc of semi-opening angle of 10 degrees produces accept able fits. The disc is found to have expanded at the start of the outburst to about 0.41R(L1), as compared with quiescent measurements. The accretion disc then gradually decreases in radius reaching < 0.32R(L1) during the las t stages of the eruption. Quiescent eclipses were also observed prior to an d after the eruption and a revised ephemeris is calculated.