ATM Effects of an inferior secondary

["Bill T." <twentiethwave@hotmail.com>]

Speaking of secondaries, who can characterize the effects of a secondary
that is less good than the primary?  What sort of defects does one see with
a crummy secondary, say on a star test?  Is it possible to sort out
secondary defects versus primary defects at the eyepiece?

Must primary and secondary PV ratings be matched for optimal performance?
Can the secondary have a somewhat poorer PV rating than the mirror, without
image degradation?

Bill T.