Elliptical Flat decision

Ok, I bought my new flat. Got a 1/14 wave Antares Pyrex with reported excellent RMS. Got a great deal on it (discounted Price,the rear edge was beveled because it had a small chip) the guy was very nice and cooperative.
Bought this one because the price was right and the quality was in line with the quality of the rest of the optics. It comes with a certificate for the Interferometer tests. Not sure if that really means anything.
I was told that it was unconditionally guaranteed to be what I wanted or my money would be cheerfully refunded! Can't ask for better than that.
Floyd

I just did a similar thing, Floyd. I just purchased a 1/25 wave (P-V) 1.3" flat from Antares for my 8" f/8. In looking at the test data, most of the error is around the extreme edge, so with a high power eyepiece, where the edge is not being used, it will be more like 1/50 wave. The nice thing about an Antares flat is that they test the flatness after it's coated, so it's definitely an accurate measurement. It may be overkill, but I will never again have to wonder if my secondary mirror is causing any image degradation.

Speaking of coatings, I was surprised to see that it has an enhanced aluminum coating. The test data they provided shows that it averages better than 95% reflectivity across the visible spectrum, as measured at 45 degrees. I was expecting just a standard aluminum coating. Plus I ordered it Friday, it arrived Monday. What a great company to deal with!

All I need now is for my Protostar curved vane (single semicircle) secondary support to arrive so that I can install it. The scope currently has a standard four vane with a "mystery" secondary that I've had in my 6" f/8 for years. I have no idea how flat it is or isn't.

I'll report once I get it all put back together.

Cheers,
Doug