Thanks Bill, yes has been a while but I started up the astro engine a few weeks back. I would LOL but that was when I had bought and owned my MK66, sold it around 2005/6 to a fellow out in your neck of the woods, it was 1/6th wave according to the ITE lab test report but the optics were extremely smooth. It is in no way scientific but from memory that scope today would compare to my Orion 150, it did take two samples from Orion to get this one but I was a first adopter on them bringing back the new version of the 150 and I kind of had the feeling that the first scopes mirror had a little flop inside the tube but I never had taken it apart. I did check this one and no mirror flop or focus shift, this is why I am very reluctant in selling this sample. That MK66 was built like a tank I kind of wish I never sold it but I bought my first C9.25 after that scope but although the optics were ok the mechanical issues were a real pain. I've owned way too many scope and not enough time, LOL.