SEMI-ACTIVE FOCUS AND THERMAL COMPENSATION OF A CENTRALLY-OBSCURED REFLECTIVE TELESCOPE

摘要

A centrally-obscured reflective telescope having a semi-active focus and thermal compensation system. The telescope has a housing having an input window, a primary mirror, a secondary mirror suspended between the input window and the primary mirror by support struts, an optional tertiary mirror, and an optional fold mirror. The system includes one or more heating elements respectively disposed on each of the support struts. A first temperature sensor (disposed on the primary mirror) generates a reference temperature, a second temperature sensor is disposed on the secondary mirror, and one or more third temperature sensors are disposed on each of the support struts. A temperature compensation controller is coupled to the heating elements and temperature sensors and controls the heat output of the plurality of heating elements to heat the support struts and control the position of the secondary mirror relative to the primary mirror.