The results of the observations are now given for each object.
The object is a strongly variable radio source with a flat radio spectrum.
The optical behaviour for the object has been monitored (e.g.
Moles et al. 1985;
Worrall et al. 1986; Falomo et al. 1989, 1993;
Xie et al. 1988) with changes
of spectral slope of 
during an optical flare of 8 days,
with variations of flux by a factor 2.5 in four days and with short
timescale (20 hours) variability with an amplitude 
0.6 mag.
Our photometry for PKS 0422+004 shows variability with maximum amplitude
about 0.4 and 0.8 mag in BV band in the interval of about one day and one
month respectively (cf. Table 2 (click here)) and the most rapid variability (timescales
from minutes to hours) which appeared in five nights. It will be seen from
the light curves in V band in Figs. 4 (click here)-8 (click here) that in 1993
November 7, the luminosity of the object decreased by 0.08 mag in 16
minutes at the begining and increased by 0.09 mag in 33 minutes at the end.
In 1993 December 4, the light curve rised by 0.06 mag in 6 minutes and fell
by about 0.07 mag and 0.11 mag in the interval of about 22 and 33 minutes
respectively. In 1993 December 5, the fastest variability occurring in 26
minutes with an amplitude of 0.17 mag. In 1994 January 6, the light curve
twice rised by 0.17 mag and 0.08 mag in the interval of about 42 and 29
minnutes respectively and fell twice 0.13 mag and 0.11 mag in the interval
of about 26 and 23 minutes respectively. Finally in 1994 January 7, the
luminosity of the object increased by about 0.31 mag in 1.5 hours.
The uncertainties of the comparison stars intercalibrated are 0.04 mag at V band for all of them and 0.04, 0.05 and 0.06 mag in B band for B, E and F respectively.
Tapia et al. (1977) discovered the BL Lacertae object PKS 0754+101 (z=0.66) during a polarization survey program. Flickering by as much as 0.8 mag is superimposed on slower variations spanning 1 or 2 years (Pica et al. 1988). Variations on time scale of a day and 80 minutes were observed by Smith et al. (1987) and Xie et al. (1991) respectively.
In our monitoring, the luminosity increased by 0.56 and 0.46 mag in the B and V bands respectively from 1991 to 1993 November and then decreased by 0.52 at B and by 0.4 mag at V in the interval of a month (cf. Table 2 (click here)), down to the level in 1991. A drop with an amplitude of 0.16 mag and then a rise of 0.14 mag in the V band were seen on time scales of about 116 and 50 minutes respectively on 1994 January 7 (Fig. 1 (click here)). The uncertainties of the comparison stars A, B, C, and G intercalibrated all are 0.04 mag at V band. In the B and R bands, the magnitudes and uncertainties of the only used comparison stars A and B are taken from Smith et al. (1985).
Figure 1: Light curve 0f PKS 0754+101 in the V band on January 7, 1994
Figure 2: Light curve of B2 1156+295 in the V band on January 6, 1994
Figure 3: Light curve of OT 081 in the V band on June 7, 1991
Figure 4: Light curve of 0422+004 in the V band in 1993 Nov. 7
The quasar B2 1156+295 (z=0.729) was first identified by Wills (1966)
as the optical conterpart of the radio source 4C 29.45 and is one of the
most variable object observed. A 5 mag optical outburst in the object
occured in the spring of 1981 (Wills et al. 1983). During our observations, the
amplitude of varitions in V band reached 1.04 mag in the interval of one month
(cf. Table 2 (click here)) and variations of 
0.22 mag were seen on
a time scale of about 2 hours on 1994 January 6 (Fig. 2 (click here)). The magnitude and its
error of the only used comparison star 15 are taken from Smith et al. (1985).
3C 334 is a radio-loud object (z=0.555) with a steep radio spectrum and flat
optical continuum. Smith et al. (1993) suggested that it has a period of
variations about 15 years. During our observations the object was fainter and
no obvious variations were seen. The uncertainties on the intercalibrated
comparison stars D and E are 
and 
for B and V band
respectively.
OT 081 (z=0.32) is a rapidly variable source. An outburst with amplitude 1.56 mag at B band was seen on April 11, 1979 (Pica et al. 1980). Rapid variations with a time scale about 40 minutes were recorded in 1990 (Xie et al. 1992).
In our observations, the V magnitude increased by 
in 15 minutes on 1991 June 7 (Fig. 3 (click here)), and in a interval of four days the
change of fluxes reached 56
in the B and V bands and 34 at R band
(cf. Table 2 (click here)). The uncertainties of comparison stars A, B, D, and G
intercalibrated at V band are 
and 
respectively, in the B band the only used intercalibrated D and G stars have
errors and 
respectively, and in the R band, the used B, D
and G stars all have a 
uncertainty.
2254+075 (OY 091) is a rapidly variable source with a flat radio and steep optical spectrum. Its redshifts (z=0.19) was determined by Stickel et al. (1988). It flared by 1.8 mag in 1981 (Pica et al. 1988). In 1987 and 1989 Xie et al. (1992) observed variations on time scales of several tens of minutes.
In our observations during 1991-1992 the object was
faint (V=17.2), No variations beyond three standard deviations were seen
on time scales of tens of minutes within one night. There were variations
mag in a interval of three days. But at
the end of 1994 the luminosity of the object increased to 
mag, and variations by 
mag
appeared in one night. On 1994 November 8 variations with
an amplitude 
mag were observed in 20 minutes in the V band
(cf. Table 2 (click here) and Table 1 (click here)). The comparison stars C, D, E,
and H are intercalibrated, their uncertainties are 
and respectively in the B band and are for C and
E stars and 
for D and H respectively in the V band. In
the R band they were 
for the C, D, H stars and 
for
the E star.
PHL 658 is active historically (Barbieri et al. 1979). In 1991-1992
our observations showed only variations by
0.1 mag in a interval of about 10 months (Guibin et al. 1995). The
present data show that the object was brightening from 1991 to
1994 and came into activity in 1994. In November/1994 variations by
mag were seen in the interval of one day
(cf. Tables 1 (click here) and 2 (click here)). Variations in short time scales are expected,
and we will go on monitoring the object. The uncertainties of the used
comparison stars A and F are the same as thoes in the
preceding paper (Guibin et al. 1995).
Figure 5: Light curve of 0422+004 in the V band in 1993 Dec. 4
Figure 6: light curve of 0422+004 in the V band in 1993 Dec. 5
Figure 7: Light curve of 0422+004 in the V band in 1994 Jan. 6
Figure 8: light curve of 0422+004 in the V band in 1994 Jan. 7
This object is a well-known variable radio quasar (Z=0.501) with a flat radio
spectrum. Moles et al. (1985) observed variability with a timescale of
105 minutes and with an amplitude increasing with wavelength reaching
0.08 mag in V band. Optical long -term monitoring (e.g.
Pica et al. 1988; Smith et al. 1993) showed a variability with 13 years period.
Our observations show no variability in the B
and V bands at any timescales.
The uncertainties of intercalibrated comparison stars are 
in the
B band and 
in the V band for both the B and G stars.