Table 1:

Parameters of the clusters' sample.

Name	RA	Dec	Age	[Fe/H]		Ref.
	hh:mm:ss	:  :	[Gyr]		[mag]
NGC 188	00:47:28	+22.384	6.0	+0.01 0.08	4.0 0.15	1
NGC 752	01:57:41	-23.254	1.6	-0.16 0.10	2.7 0.20	2
NGC 2420	07:38:23	+19.634	2.1	-0.26 0.07	3.3 0.20	3
NGC 2477	07:52:10	-05.850	0.8	+0.07 0.03	1.9 0.25	4
NGC 2506	08:00:01	+09.935	1.9	-0.37 0.02	3.1 0.25	5
NGC 2509	08:00:48	+05.820	1.2	+0.00 0.10	2.5 0.20	6
M 67	08:51:18	+31.896	4.0	+0.00 0.01	3.8 0.10	7
NGC 3680	11:25:38	+16.918	1.8	-0.16 0.03	2.9 0.15	8
NGC 6134	16:27:46	-00.200	1.0	+0.18 0.10	2.0 0.15	9
NGC 6253	16:59:05	-06.260	3.0	+0.36 0.07	3.7 0.15	10
IC 4651	17:24:49	-07.907	1.1	-0.11 0.01	2.1 0.20	11
NGC 6819	19:41:18	+08.481	2.5	+0.09 0.03	3.4 0.25	12
NGC 6939	20:31:30	+12.304	2.2	+0.02 0.05	3.2 0.15	13
NGC 7789	23:57:24	-05.385	1.4	-0.10 0.05	2.4 0.20	14

The last column gives a reference to the literature source of the adopted cluster age and metallicity.
1) Fornal et al. (2007); 2) Anthony-Twarog & Twarog (2006); 3) Anthony-Twarog et al. (2006); 4) Kassis et al. (1997); 5) Marconi et al. (1997); 6) Carraro & Costa (2007); 7) Sarajedini et al. (2009); 8) Anthony-Twarog & Twarog (2004); 9) Bruntt et al. (1999); 10) Twarog et al. (2003); 11) Meibon et al. (2002); 12) Kalirai et al. (2001); 13) Andreuzzi et al. (2004); 14) Vallenari et al. (2000).