كرة نقل F/3.3 - 4 بوصات - موجة 1/20، PVr

Interferogram after interferogram, the surface stays dead flat—that 1/20 wave spec is real, not marketing fluff. Fit it to my interferometer and it just works, no surprises.

The wavefront error on this 4-inch F/3.3 sphere came in exactly as spec’d—my interferogram was clean across the full aperture. It’s noticeably heavier than my old one, which actually helps with thermal stability during long sessions.

Swapped this 4" sphere into my F/3.3 setup and the fringe quality is noticeably cleaner than the older one it replaced. Surface figure holds up well across the full aperture, no obvious astigmatism when I rotate it.