Table 2: Observed mean R_C magnitudes and rms deviations for our Loiano and Asiago observations. The last column report the fiducial border line value, discussed in the text, for each source.

Source name	2QZ r	Loiano	rms	N	Asiago	rms	N	Border-line
2QZ J100253.2-001728	19.03	19.03	0.04	4	19.05	0.03	8	0.05
2QZ J102615.3-000630	19.17	19.04	0.02	6	19.03	0.03	5	0.05
2QZ J103607.4+015658	18.57	18.51	0.03	5	18.51	0.03	5	0.04
2QZ J104519.7+002615	18.43	18.43	0.02	5	18.50	0.02	4	0.04
2QZ J105355.1-005538	19.09	19.23	0.07	7	19.29	0.04	5	0.06
2QZ J105534.3-012617	18.50	18.09	0.01	2	18.12	0.05	4	0.03
2QZ J110644.5+000717	>20.93	20.33	0.25	5	20.39	0.05	6	0.14
2QZ J113413.4+001041	18.25	18.18	0.02	7	18.26	0.05	4	0.03
2QZ J113900.5-020140	18.76	18.72	0.06	5	18.74	0.03	4	0.04
2QZ J114010.5-002936	19.97	19.88	0.09	9	19.96	0.07	6	0.12
2QZ J114137.1-002730	18.71	18.85	0.06	7	18.95	-	1	0.05
2QZ J114521.6-024758	18.53	18.46	0.01	5	18.50	0.01	3	0.04
2QZ J114554.8+001023	19.46	19.45	0.03	6	19.48	0.04	2	0.08
2QZ J115909.6-024534	18.77	18.68	0.04	5	18.74	0.05	3	0.04
2QZ J120015.3+000552	18.63	18.58	0.02	5	18.64	0.02	2	0.04
2QZ J120558.1-004216	18.46	18.62	0.02	5	18.63	0.01	3	0.04
2QZ J120801.8-004219	18.86	18.90	0.02	4	18.96	0.01	2	0.05
2QZ J121834.8-011955	18.25	16.60	0.16	5	16.25	0.05	2	0.01
2QZ J122338.0-015619	18.85	18.96	0.01	5	19.04	0.03	1	0.05
2QZ J123437.6-012953	18.97	18.73	0.05	5	18.76	0.02	1	0.04
2QZ J125435.7-011822	18.81	18.87	0.04	4				0.04
2QZ J130009.9-022601	18.67	18.77	0.03	6	18.78	0.01	3	0.04
2QZ J131635.1-002810	19.53	19.44	0.03	6				0.08
2QZ J132811.5+000227	19.79	19.71	0.09	5	19.77	0.05	3	0.10
2QZ J140021.0+001955	19.30	19.53	0.07	8	19.51	0.03	3	0.08
2QZ J140207.7-013033	20.14	19.73	0.08	8	19.87	0.05	4	0.10
2QZ J140916.3-000012	18.47	18.41	0.02	8	18.45	0.01	2	0.04
2QZ J141040.2-023020	19.27	18.68	0.01	6	18.73	0.03	6	0.04
2QZ J142526.2-011826	19.47	19.24	0.01	2	19.31	0.01	2	0.08