F/25 Converger 4"

The wavefront error came in right at the spec, and the 1/10 wave PV is spot on for our setup. I've used pricier convergers that didn't hold up as cleanly in the null test, so this one's a keeper.

Checked the interferogram on our 4-inch setup and the fringes came through dead straight—that 1/10 wave PV is doing exactly what it should. Snugged right into the mount without any wobble, so alignment took minutes instead of an afternoon. This converger’s earned a permanent spot on the bench.

The 1/10 wave PV figure isn't just marketing talk — I checked it against my reference flat and the fringes stayed dead straight across the whole 4" aperture. Focus holds nicely at f/25 too, so collimation barely drifts between sessions.