Flickering is a well-known, though poorly understood, signature of accretion in cataclysmic variables. HT Cas is an excellent system in which to study flickering because its well determined characteristics allow a calibration of the experimental system (see Horne et al. 1991).
Patterson (1981) argues that the flickering in HT Cas originates from regions very near the white dwarf. In U Gem, the flickering appears to be associated with the bright spot (Warner & Nather 1971). In RW Tri, the flickering occurs throughout the disk but is centrally concentrated (Horne & Stiening 1985); the same holds true for V2051 Oph (Warner & Cropper 1983).
HT Cas is a 16m.4 eclipsing dwarf nova with a binary period of 106 min and an inclination of ∼ 81°. The entire eclipse last about 15 min with the white dwarf totally eclipsed for ∼ 5 min. The mass ratio is 0.15 with the white dwarf having mass ∼ 0.6M
⊙ (Horne et al. 1991).
We obtained 20 eclipses of HT Cas between 1982 and 1991 in U, B and V at Mt. Palomar and also McDonald Observatory with 0.5 – 2 sec integrations. These data were folded on the ephemeris given by Horne et al. (1991) and corrected for the 30 sec drift in the phasing as noted by Wood et al. (1995).