Comments on diagonal Zygo

I received the Zygo test of the diagonal mirror which was rated at 1/20 th wave at purchase. Can the optical pundits comment what they see ?
The edge defects (left) are from the silver layer corrosion.

Edit add-on: my take is that there is a middle zone ca. 1" long which falls into the 1/20th wave (0.05) when I look on the surface profile. So I would say not so super bad as I understood initially when one considers that just center of the mirror would be used (in contrary to a diagonal in a reflector).
Still, with $50 asked for recoating, I can better go for a new $58 dielectric 1/10 wave glass from WO...

Attached Image:

This is a mirror in a star diagonal or an elliptical flat? It looks like a flat, but then you describe a star diagonal mirror.
If this is a flat, then if it were installed into a holder, the edges would be covered by the lip of the holder and the worst of the problems would gone. There is a peak on one end and another anomaly on one side, but these are both just on the edge. The peak on the end would effect the P/V greatly. Without that peak, the P/V would be much better.
Now, the way you are talking this is in a star diagonal. If this is true, then the edge peak does not come into play, nor would the other anomaly because they are outside of the area in use with a star diagonal.
so, which is it?

Agreed this one does not look too bad. Much of the
error will manifest itself as a simple change in focus,
so while the zone is 1/20th wave it will seem like much less.
Probably harmless focus change + 1/50th wave astigmatism
for an F/3 scope. Something like 1/100th wave astig for more
reasonable F/6 scope.

I might go with this one vs. new one. For this one you've
got the interferogram and pretty much know what you've got.

I am not sure, but I think these may be surface errors, not
wavefront errors on the plot. So wavefront errors would
be twice as large. Even so, it is still very very good.

>>I received the Zygo test of the diagonal mirror which was rated at 1/20 th wave at purchase. Can the optical pundits comment what they see ?
The edge defects (left) are from the silver layer corrosion.
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David:

Who performed the test for you and how much did it cost? A couple of years ago when I was looking into testing a 3.1 inch secondary on a Newt, I was told that it would be so expensive that it was not worth it...

Jon