Table 1: The list of Vilnius photoelectric standard stars observed in the studied fields and used for calibration.

N.Zda	S66	M92C	V	P-X	X-Y	V-S
4	IX-13	38	14.00	0.58	0.88	0.75
8	X-49	2	12.21	0.91	1.22	0.90
9	III-65	7	12.47	0.89	1.28	0.91
6	IV-40	35	13.88	0.58	0.88	0.75
		M92W	V	P-X	X-Y	V-S
1	VI-7	10	13.50	0.60	0.81	0.59
2	VII-18	2	12.15	1.04	1.37	0.93
6	IV-40	15(35C)	13.88	0.58	0.88	0.72