Progress in ground-based optical telescopes

Abstract

For several decades, the 5 metre Palomar telescope has set a practical limit to the size of ground-based optical telescopes only exceeded by the Russian 6 metre telescope. Using new technologies to produce either large monolithic mirrors or large mosaic of smaller elements, astronomers in Europe, the United States and Japan are developing a new generation of telescopes. Not only are these new telescopes much bigger in size, offering considerably more collecting power, but they also provide a much better angular resolution. To achieve this they rely heavily on computer control techniques and advanced modelling. Even more progress in angular resolution is expected when modern techniques such as adaptive optics and interferometry, which are being implemented on most of the new telescopes, are fully operational. This article evaluates the impact of new technologies on the development of large optical telescopes, in particular on the realization of their optics. The key mirror technologies are reviewed and a particular project, the ESO VLT is reviewed in some more detail as an illustration.

The Design and Construction of Large Optical Telescopes

“…This method is used by REOSC, for which they have developed an analysis software referred to as "flow interferogram processing" (FLIP) [62]. This method is used by REOSC, for which they have developed an analysis software referred to as "flow interferogram processing" (FLIP) [62].…”

Deconvolution with Correct Sampling

“…Much effort is presently devoted to the improvement of the spatial resolution of astronomical images, either via the introduction of new observing techniques (e.g. interferometry or adaptive optics, see Léna 1996, Enard et al 1996 or via a subsequent numerical processing of the image (deconvolution). It is, in fact, of major interest to combine both methods to reach an even better resolution.…”

Adaptive SPECT

“…It is sometimes useful to separate the effects of the imaging aperture and detector from the patient-dependent effects of attenuation and scatter. We can describe the latter by a linear operator , so that the overall system operator is ℋ = ℋ 0 and (2) The operator maps the primary-energy radiation emitted by the object to a phase-space distribution function which specifies the photon density as a function of spatial position, photon propagation direction, and energy. The spectrum of energies and propagation directions results from Compton scattering in the object.…”

“…With the general adaptive template w(g s ) as in ( 9) and the assumptions listed at the beginning of this section, the difference of means, which appears in the numerator of SNR 2 , becomes [cf. (41)] (48) where the term c(g s ) has cancelled on the assumption that the scout system responds just to the background.…”