A Detail Review of Optical Misalignment and Correction by Refocusing Mechanism

When light rays enter in satellite telescope, it first travels to the primary mirror than reflects back towards the secondary mirror and henceforth setting a focal point after passing through the centrally provided hole on primary mirror in case of Cassegrain focus. Generally, space borne telescope are subjected to orbital loads like temperature excursion, absences of gravity, moisture release of metering structure etc. which leads to coefficient of thermal expansion and coefficient of moisture expansion of metering structure. Due to this there is the change in focal length & misalignment of optical system which ultimately reduces the quality of images. The actual location of focal point is very important for qualitative images. So to get the perfect focal point, it is necessary to reset the distance between primary and secondary mirror by means of some actuating mechanism. This distance can be corrected with the help of re-focusing mechanism & concept modification of the mechanism is discussed over here.