Aperture extender for autocollimators and telescopes having index-matching gel or fluid between prism facets

A method for assessing and correcting inaccuracies in rhomboidal prisms integrated into an aperture extender system, the method comprising:

• projecting a calibration beam from an autocollimator through a first rhomboidal prism and a second rhomboidal prism;
• receiving partial back-reflections generated by partial-mirror coatings on facets of each rhomboidal prism;
• detecting the back-reflections with an imaging sensor of the autocollimator;
• identifying, via wavelength separation or coating characteristics, which back-reflections correspond to which rhomboidal prism;
• computing, by a microprocessor, angular and positional deviations attributable to manufacturing or alignment imperfections in each rhomboidal prism;
• and
• applying correction data to measurements acquired through the aperture extender system to compensate for the computed deviations, wherein an index-matching gel or fluid disposed between adjacent prism facets reduces inter-reflections that would otherwise corrupt the diagnostic reflections.

A method of operating an aperture extender system for optical devices, the method comprising:

• interconnecting a first rhomboidal prism and a second rhomboidal prism in series;
• securing the first rhomboidal prism to an autocollimator's aperture using a first rotating coupling that allows rotation about the autocollimator's optical axis;
• employing a microprocessor to compute the measurement of back-reflected beams concerning the rhomboids' positions, detecting imperfections in the rhomboids' manufacturing;
• utilizing distinct partial mirror coatings on the rhomboids and processing reflected images to assess the deviation in the line of sight caused by their positioning;
• and
• attaching a second rotating rotating coupling to an exit facet of the first rhomboidal prism to support rotation of the second rhomboidal prism about an axis of an exiting beam;
• filling a sealed cavity between adjacent prism facets with an index-matching gel or fluid to eliminate inter-reflections during rotation;
• generating partial back-reflections from partial-mirror coatings on facets of the rhomboidal prisms;
• processing the reflected images to determine line-of-sight deviations introduced by prism positioning or imperfections;
• and
• computing by a microprocessor, correction values based on the back-reflections to compensate for prism-induced deviations during measurement.