The traditional manual method is adopted to process the lager diameter parabolic and hyperbolic lens with BK7 (ZK N4 or Zerodur) material, use knife-edge instrument for test, with high processing accuracy, and the diameter can be within 900mm.surface accuracy could be less than 1/40 lambda.
| Material | BK7, ZK N4 ,Zerodur ect. |
| Diameter tolerance | +0.0/-0.15mm |
| Diameter | ≤900mm |
| Aspherical surface | Parabolic, Hyperbolic |
| Focal length tolerance | ±2% |
| Clear aperture | ≥90% |
| RMS Irregularity | 1/40λ |
| Surface Quality | 60-40 |
| Bevel | 0.25 mm × 45° |
| Coating | Metal reflection coating/Dielectric reflection coating |
