The construction of telescope systems with large apertures (≃10 meters) is currently being planned. These entire telescope systems should be optically tested in a double-pass configuration. The high cost of manufacturing optical flats large enough to test a large telescope has stimulated research on a new type of testing in which several smaller flats, or subapertures, are distributed over the telescope aperture. The problem is to combine the partial data obtained only over the subapertures in order to obtain the wavefront over the entire aperture. It was the purpose of this dissertation to prove experimentally that subaperture testing is feasible. The question of the necessity of phasing the subapertures relative to each other was specifically addressed in the experiment. A brief review is given of two algorithms utilizing Zernike polynomials. A third subaperture testing analysis algorithm, the Stuhlinger method, is developed in this work; this provides raw phase data over the entire aperture of the system under test. A statistical analysis of this algorithm is given. A 6 in. diameter array of seven subapertures was used in this small-scale test. Data were obtained with the array, a monolithic flat, and a mask simulating the array placed over the monolithic flat. The results of the experiment are in good agreement with control data measured with a Zygo interferometer. Data and analysis for the Stuhlinger method are also presented. Error analysis shows that Zernike coefficients derived using subaperture testing are 5 times less accurate than those derived using monolithic testing for the subaperture configuration used here. It is shown that knowledge of the subaperture tilts can produce accurate wavefront information with as few as 30 data points per subaperture, as compared with 750 data points per subaperture if tilts are unknown. In conclusion, subaperture testing indeed functions in the absence of subaperture phasing. Tilt information influences mostly the lower order Zernike coefficients; lack of such information may be compensated by the use of more data points. Algorithms yielding either Zernike coefficients or raw phase data were shown to function. (Abstract shortened with permission of author.)

Thesis (M.S.)--University of Hawaii at Manoa, 207. / Includes bibliographical references (leaves 82-84). / x, 84 leaves, bound ill. 29 cm

James W. Mar and Harold Liebowitz, editors. / Co-sponsored by the Office of Naval Research and the Massachusetts Institute of Technology. / Includes bibliographies.

International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Astronomers now communicate over Internet with robotic astronomical telescopes using a specially designed instruction set. ATIS, Automatic Telescope Instruction Set, is designed to communicate specific, technical instructions to a robotic telescope, facilitate data retrieval and analysis, support a wide range of data formats, and also convey preference information that describe the astronomers general needs for data acquisition. Over a dozen telescopes now use ATIS and more are under construction.

No description available.

No description available.

For precision spacecraft structures used for antennas and reflectors of telescopes, determination of in-orbit structural displacement and its control is very important. While this kind of measurement is relatively easy to carry out in a laboratory setting, it can be problematic in a real world environment. A procedure for the real-time determination of displacements at any point of a vibrating body can be utilized by measuring strain that is present. The procedure could employ measurement devices like Fiber Bragg Gratings, which are capable of very fine strain measurements. This thesis presents the finite element analysis of a truss similar to the NPS Space truss to observe the behavior of the strain relative to the displacement. A relationship between strain and displacement for the truss is derived.

published_or_final_version / Physics / Master / Master of Philosophy

Large aperture astronomical telescopes have a resolution that is limited by the effects of the Earth's atmosphere. The atmosphere causes incoming wavefronts to become aberrated, to correct for this adaptive optics is employed. This technique attempts to measure the incident wavefront and correct it, restoring the original image. Conventional techniques use mirrors that are deformed with piezo-electric crystals, this thesis uses an alternative technique. Two different types of liquid crystal spatial light modulators are used as the corrective elements. The advantages and disadvantages of both are assessed in an attempt to find which system is the best for astronomical adaptive optics.

Thesis (MEng(ElectricalEngineering))--University of South Australia, 2004.