24 Inch 4% Reference Flat

The aperture is genuinely huge, and the 4% reflectivity paired with the 1/10 wave PVr made my calibration checks much more reliable. It took a bit of careful handling to get it set up, but the surface quality is exactly what I needed for precise work.

Tested it on my interferometer and the 1/10 wave surface figure held up across the whole 24 inch aperture, no surprises at the edges. At 4% reflectivity it does exactly what a reference flat should without ghosting.

Ordered this 24 inch flat to check our interferometer setup and the surface didn't disappoint. The 1/10 wave PVr spec held up under testing, and at 4% reflectivity it's exactly what we needed for our reference work without blinding glare.