Abstract: Two reflective surfaces disposed in a predetermined angular orientation inside the optical tube assembly of a telescope intercept the optical beam and deliver it from the objective to the eye-piece. By translating these surfaces simultaneously along the axis bisecting the angle between them, the separation between the focal points of the objective and the eye-piece is adjusted as required to re-focus the telescope in a continuous and reversible fashion without changing its overall dimensions.

Abstract: A targeting unit is incorporated into the main body of a solar telescope. The targeting image is provided by an aperture facing the sun in the housing of the telescope through which sunlight is received and directed to a transmissive viewing screen placed in the housing on the same side of the telescope's eyepiece. All parts of the targeting system are fixed to the housing of the telescope and removed from accidental contact by personnel operating the telescope, thereby minimizing the chance for events that might cause misalignment. In addition, this configuration makes it possible to easily position both the viewing screen and the eyepiece on the same side of the telescope following any degree of folding of the objective beam.

Abstract: A solar filter assembly combines a high-precision Fabry-Perot etalon with a variety of conditioning filters judiciously selected to effectively block completely all radiation except for the spectral line of interest. In addition, a tuning mechanism is provided to precisely control the peak frequency of the filter's output by varying the optical length of the etalon's cavity.

Abstract: A compressive force is applied to a conventional air-spaced etalon filter to fine tune the thickness of the spacers to a precise and uniform optical length. The etalon is coupled to a housing device capable of adjusting the thickness of each spacer, thereby tuning the etalon to the desired filter wavelength. The resulting assembly is permanently set to the desired parameters for direct use in optical applications.

Abstract: Two reflective surfaces disposed in a predetermined angular orientation inside the optical tube assembly of a telescope intercept the optical beam and deliver it from the objective to the eye-piece. By translating these surfaces simultaneously along the axis bisecting the angle between them, the separation between the focal points of the objective and the eye-piece is adjusted as required to re-focus the telescope in a continuous and reversible fashion without changing its overall dimensions.

Abstract: A targeting unit is incorporated into the main body of a solar telescope. The targeting image is provided by an aperture facing the sun in the housing of the telescope through which sunlight is received and directed to a transmissive viewing screen placed in the housing on the same side of the telescope's eyepiece. All parts of the targeting system are fixed to the housing of the telescope and removed from accidental contact by personnel operating the telescope, thereby minimizing the chance for events that might cause misalignments. In addition, this configuration makes it possible to easily position both the viewing screen and the eyepiece on the same side of the telescope following any degree of folding of the objective beam.

Abstract: A hybrid sol-gel material is placed in optical contact with two optical surfaces and the surfaces are precisely aligned as necessary to meet desired optical specifications. The sol-gel material filling the gap between the surfaces is then cured, such as by exposure to UV radiation. This allows, for example, the fabrication of a solid-spaced etalon filter where the spacer layer of the etalon is formed with sol-gel material to a precise dimension defined by the alignment of the optical surfaces. The optical properties of the hybrid-glass structure formed between the optical surfaces may be fine tuned by varying the exposure of the sol-gel material to the curing agent. Furthermore, the hybrid-glass structure of the invention can be patterned using standard photolithographic techniques.

Abstract: A solar filter assembly combines a high-precision Fabry-Perot etalon with a variety of conditioning filters judiciously selected to effectively block completely all radiation except for the spectral line of interest. In addition, a tuning mechanism is provided to precisely control the peak frequency of the filter's output by varying the optical length of the etalon's cavity.