Product Description
This is an 8 inch diameter spherical radius test plate with both sides figured. The plate has a measured radius of 38.4747 inches. The center thickness is 0.940 inches. The power is lambda / 4, peak-to-peak. Similarly the irregularities are also lambda / 4 peak-to-peak.
The plate was manufactured by Itek for use in a null test application. Originally there were two plates (a CX-1 and a CC-1). Only the CC-1 plate is present.
Itek was the prime contractor for very high-end optics used in military applications, notably imaging systems for National Security Agency spy satellites.
Photo set 1679