We take quality control very seriously: we rely on accurate, widely recognized measurement systems for testing our optics. The following table indicates the accuracy of measurement for the most relevant parameters.
Surface figure: λ/20
Angle: 0.5 arcsec
Focal length: 0.03%-0.3%
Centration: +/-0.2µm or +/-2 arcsec
Wavelength: +/-0.3nm (190-1100nm)