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In the course of the blazar monitoring activity at the Torino Astronomical Observatory, we obtained standard BVR magnitudes for 36 stars and standard VR magnitudes for 10 stars in the fields of 9 quasars. Observations were done during 14 photometric nights with the Cassegrain REOSC telescope equipped with a pixel CCD camera. All stars are brighter than and are useful comparison objects for the evaluation of the quasar magnitudes.
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Raiteri et al. (1998) studied this question.
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