All Reflective, Off Axis, Unobscured, Wide Field Relay Optics

This system relays a pupil approximately 60cm away in X and 1.3 meters in Z. It is designed to withstand high levels of acceleration, shock, and vibration. Overall dimensions are 37"x28"x35" and weighs just under 180lbs.

Four free-form mirrors collect and reflect incoming light which required different tests to validate the performance of the system. The exit pupil location needed to be precisely defined and qualified at a location approximately 1 meter outside of the instrument. To verify this, a carbon fiber truss structure was used to locate a set of test retro mirrors at the prescribed exit pupil location. Fine positioning of the retro mirrors relative to datums on the assembly breadboard was accomplished using a large bridge style coordinate measuring machine (CMM). The mirror locating references were bonded in place after alignment was established with the CMM. The optical performance was testing in two ways: interferometrically in a double-pass setup, and by measuring the PSF directly with a camera and lens.

Before production of the relay system, a dynamic Structural-Thermal-Optical-Performance (STOP) analysis was performed on the design using our CAD software package. The optical response was modeled for the shock and sinusoidal forcing function. From this, we created animations of the mirror deformations and the system spot diagrams to validate the design before sending to manufacturing.