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Table 2

List of reference stars.

α (J2000)   δ (J2000)   B V R I

00:42:08.9   +40:55:33   14.521   13.739   13.312   12.886
00:42:12.6   +40:54:38   14.792   14.267   13.996   13.699
00:42:12.2   +40:55:49   16.030   15.287   14.883   14.495
00:42:05.3   +40:53:38   16.876   15.915   15.381   14.822

rms of calibration   0.015   0.007   0.008   0.015

Notes. The magnitudes are calibrated by the Massey et al. (2006) catalogue using images from the 6 m BTA, the Rozhen 2 m and the Konkoly Schmidt telescopes.

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