Exemplary testing systems and methods are provided including a system configured to test for thermal drift of a unit under test (UUT) under various temperature or environmental conditions and generating an output including visual or data on the thermal drift, if any. The methods involve attaching a UUT to a mounting device within a thermally controlled chamber, collimating light received from a UUT, recording the resulting images, and comparing the results at different temperatures to determine how much thermal drift has occurred. In addition, there are testing apparatuses capable of performing the tests.