Absolute magnitude of confirmed cluster members (HCG 22 are filled red circles, HCG 90 are black squares) vs. the ratio between the cross-correlation amplitude using our reference old stellar template and an intermediate age template (3 Gyrs,  [Fe/H]  = −0.5   dex; Coelho et al. 2007). Negative to positive values indicate spectra better fit by young to old ages, respectively. Objects marked are the ones with cross-correlation confidence level higher than 5.