Monitoring Small Deformations In An Instrument

Relatively simple source/detector pairs measure changes affecting optical alignment. System for monitoring small thermal, gravitational, and dynamical deformations in x-ray telescope includes two sources of infrared light, each associated with dual-axis, position-sensing photodiode. Principle of operation straightforward and applicable to monitoring of small lateral translations and/or rotations between different parts in machinery, buildings, bridges, ships, and other large structures.