كرة نقل F/3.3 - 4 بوصة - كرة فائقة 1/40 موجة (15.8 نانومتر) PVr.

Took a gamble on the 1/40 wave specification, and the interferogram came back cleaner than I've gotten from pricier spheres. The 4-inch aperture paired with the F/3.3 design is a solid match for my current setup, no complaints on the surface quality.

Set up was straightforward and the coated optics are flawless—interferometer fringes came in crystal clear immediately. Testing a fast parabola, the 1/40 wave accuracy really shines through on the return wavefront. Exactly what I needed for my shop.

The 1/40 wave surface figure on this 4" sphere is genuinely impressive — our interferometer traces come back noticeably cleaner than with our old standard-grade optic. Getting down to 15.8nm PVr made a real difference in our F/3.3 null tests.