FC detection limits for PC images of Gl 144 ( Eridani) through (a) F1042M and (b) F814W. This star’s V magnitude is average for the targets in group 2; the detection limits are therefore typical for group 2 targets. All curves and symbols are as described in the legend to Fig. 2 and in § 3.1. The discontinuity in the F814W 10 σ curve at ~1﹩\farcs﹩5 marks the transition between the shorter (4 s) and longer (40 s) exposure sets.