Table 1: Fundamental parameters of the clusters under study, taken from WEBDA.

Name	l	b	Radius	(m-M)V	E(V-I)	age
	deg	deg	arcmin			Gyr
NGC 7789	115.53	-5.38	14.0	12.5	0.27	1.7
Berkeley 66	139.43	+0.22	2.0	17.5	1.55	5.0
Berkeley 70	166.89	+3.58	2.5	14.6	0.60	4.7