Risley prism based star tracker and celestial navigation systems

An optical system, comprising:

• a first pair of prisms positioned along an optical axis to receive a light beam from a field of view (FOV);
• a light shade having an input end and an output end, the light shade positioned along the optical axis and configured to receive, at the input end, the light beam from the first pair of prisms, the light shade including a hollow interior defined by an inner surface that is configured to block one or more rays of the light beam that are from outside of an FOV of interest as the light beam passes through the light shade, wherein at least one ray of the light beam that is from the FOV of interest passes through the output end of the light shade;
• at least one lens positioned along the optical axis to receive, from the output end of the light shade, the at least one ray of the light beam that is from the FOV of interest, and any rays of the light beam that are from outside of the FOV of interest that pass through the light shade;
• and
• an optical detector device positioned along the optical axis, the optical detector device including an optical detector array and a light blocker section that surrounds the optical detector array, wherein the optical detector array receives, from the at least one lens, the at least one ray of the light beam that is from the FOV of interest, wherein any rays of the light beam that are from outside the FOV of interest that pass through the at least one lens are blocked by the light blocker section.