The method of data reduction had been detailed in the previous paper (Guibin et al. 1995). The comparison stars are intercalibrated. All observations are reduced by relative photometry against the comparison stars in the same frame and the weighted average of extinction values of the comparison stars is used to calibrated the object. The uncertainty of the final magnitude of the object contains the errors of measured magnitudes of the comparison stars and the object and the uncertainties of magnitudes beyond the atmosphere for the comparison stars. The results obtained for the objects are listed in Table 1 (click here). The weighted average of the magnitudes and colour indices, which are calculated by two subsequent observations of different colours each night are tabulated in Table 2 (click here).
Table 1: Observation for 8 blazars
Table 2: Average colour indices and average magnitudes of 8 blazars
