We study exactness and maximal automorphic factors of C-3 unimodal maps of
the interval. We show that for a large class of infinitely renormalizable m
aps, the maximal automorphic factor is an odometer with an ergodic non-sing
ular measure. We give conditions under which maps with absorbing Cantor set
s have an irrational rotation on a circle as a maximal automorphic factor,
as well as giving exact examples of this type. We also prove that every C-3
S-unimodal map with no attractor is exact with respect to Lebesgue measure
. Additional results about measurable attractors in locally compact metric
spaces are given.