This long-focal-length, full-thickness Pyrex mirror has quality written all over it (not literally!) Sourced from a Raytheon optical facility, it's in excellent condition in every way and comes mounted on a lab-grade 3-point adjustable optical mounting (probably worth a few hundred by itself). Everything about its appearance speaks of a laboratory-grade, EXPENSIVE piece of glass.
I examined its Ronchi images at ROC and included below a representative 'in & out' snapshot so you can judge for yourself. The bands are only slightly curved, as is appropriate for a f/10 figure. The surface is nice & smooth, with a good edge and only a very slight deviation near center (mostly covered by the secondary, I would think, especially if used in a folded Newtonian). Being no optical expert, I asked our local optical expert his opinion - he felt that it should provide nice diffraction-limited images. This could make a truly special instrument.
So consider giving this unique mirror a good home - it's a rare find. I'm asking $650 OBO plus shipping (it's pretty solid at 35 lbs, with mounting - 22 lbs without). If you're interested in just the mirror or just the mount, let me know. PayPal acceptible (split the fee), or other payment arrangements as necessary (M.O., etc.)
Give this nice piece of glass a chance to collect photons and build it into a nice optical system. See my ratings. Thanks for looking & Clear Skies!