كرة نقل 4 بوصة، F/7.1، 1/20 موجة

The fringe contrast on my interferometer setup improved noticeably right out of the box, and the 1/20 wave surface figure is clearly doing its job. I've tested it against a reference flat and the f/7.1 cone is clean edge to edge, no zonal errors jumping out.

The f/7.1 focal ratio paired with the 1/20 wave PV spec gives me real confidence in the surface accuracy—interferograms come out clean without ghosting artifacts. Setup was straightforward, and the housing feels solid enough for bench work.

I’ve been using this sphere for wavefront testing, and the fringe contrast is sharper than with my older reference. The 1/20 wave figure really does clean up the mid-spatial errors I was seeing before.