2 New observations and data reduction

As a new attempt to study its possible period variation by the "$\rm O-C$'' technique, photometry on VZ Cnc was made at Xinglong station of Beijing Astronomical Observatory with a 60 cm reflector plus a CCD camera on December 19, 1995. The filter used was a Johnson V. After careful extinction correction on the raw magnitudes of the variable star, one new time of maximum light is determined thus: $T_{\rm max}=$ HJD 2450071.2820. This new time is combined with the times listed in the literature and 138 times of maximum light are collected and then listed in Table 1.

  

Table 1: Times of light maxima of VZ Cnc

Besides this, some high-quality observation data for VZ Cnc are collected from the literature. Table 2 lists the journal of these observations.

  

Table 2: Journal of the observations for VZ Cnc in the literature