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In the late 1970s, an intense effort was already well established within the astronomical communities of the United States, Europe, and Japan to produce a multipurpose telescope with an aperture measuring 8-10 meters in diameter. At the same time, the U.S. Department of Defense was investigating a wide range of problems dealing with the propagation of directed electromagnetic energy beams through the atmosphere. The field of active optics, a companion to the field of active structures, contains studies relating to the control of optical surfaces at relatively low bandwidths and spatial frequencies. The 'tuning' of a large primary mirror support system in real time, for example, to correct for inaccuracies, hysteresis, and thermal perturbations in a slowly moving telescope mount is by now a well-understood problem in active optics. A large body of research by investigators at NOAO, ESO, the JNLT project, and various observatories including Keck, McDonald, Steward, and others has led to a fairly consistent approach to such problems, for both continuous and segmented substrates. Almost without exception, the structural models may be designed in terms of a linear elastic system whose vector basis is derived from the fundamental theories of Fourier analysis, Bessel functions, Kelvin functions, and Zernike polynomials, or, when optical structures are not so easily represented by closed forms in the theory of elasticity, in terms of basis vectors gleaned from various numerial analysis methods, including the finite element method. Although several years ago Ray presented an active primary mirror support system based on a modal space derived from finite element techniques, Noethe (European Southern Observatory) has recently presented a more concise justification for this, linking the modal basis derived from the classical theory of elasticity to a similar one emanating from finite element dynamic analysis.