Anyone ever looked through a Coultier 13" ?

I was wondering what the concensus was about these scopes/mirrors...anyone have any thoughts on it?

They were good in their day, but today's dobs are far better in quality.

The one I looked through a couple years ago showed sharper planetary images than a nearby C14. Masking the Coulter down to 5" improved its planetary performance somewhat. This indicates that the total wavefront error on the Coulter was significant and masking down reduced this by finding a good spot on the mirror. My modern 16" dob was noticably sharper than the Coulter. The 16" performs better at full aperature than when masked down. This indicates good wavefront correction over its entire surface.

The quality of the Coulter mirrors was basically a crap shoot. You just hoped you got lucky and got a decent one. One friend's 10" is one of the nicest 10's I've ever seen and another had a decent but not outstanding 13.1" mirror. My 17.5" suffered from horrible astigmatism and never performed worth a crap. Unfortunately I bought this mess from someone else second hand and had to live with it.

Don W