The observations were designed to reach oldest MS turnoffs at MI = +3 with good photometric accuracy, in order to obtain detailed SFHs (S/N >10 @ MI = +3 ; S/N=5 @ MI =+4).
Choice of bands: the combination F475W-F814W was found to be the most efficient to trace age differences at old ages
Parallel WFPC2 observations reach MI = +2.5 with S/N=10; these will be used to study outer halo fields in each galaxy
