Astronomy optical

Running in parallel to spectacular space-based astronomy, optical telescopes and radiotelescopes have progressed in a quite breathtaking manner thanks to the new techniques of interferometry and active and adaptive optics. Telescopes perched on mountain peaks, such as the CFHT (Canada-France-Hawaii Telescope) and Keck on Mauna Kea in Hawaii and the VLT on Cerro Parana in Chile, and radiotelescopes set out like windmills in Puerto Rico, Sologne (in the French Alps), The Netherlands and Spain, gather photons able to cross the layers of the atmosphere without major alteration, whilst spectrographs then dissect the radiation into its finest detail. 

Cavendish explored all areas of science, including astronomy, optics, electricity, geology, and pure mathematics. Among his accomplishments are the first calculation of Earth s mass (his results were just 10% off modem measurements) and the introduction of the concept of voltage. His principal interest nevertheless was experimental chemistry. His most famous contribution to science was the discovery and description of the properties of hydrogen and its status as a constituent element in water. 

They translated Aristotle and studied his works they cultivated astronomy, optics and the various branches of medicine and they enriched these sciences with new truths. We owe to them the spread of the use of algebra, which had been applied by the Greeks only to one class of problem. If it is true that their fanatical interest in the secrets of alchemy and the elixir of life sullied their work in chemistry, it must be remembered that it was they who revived, or rather invented, this science which had till then been confused with pharmacy or with technical skill in the arts. It was with them that chemistry appeared for the first time as the analysis of bodies into discernible elements and as the theory of their compounds and the laws of such compounds. 

Besides being one of the most accomplished chemists of his time, Wollaston was eminent in other fields. His 39 papers in the Philosophical Transactions (out of a total of his 56 publications) deal with astronomy, optics, mechanics, acoustics, mineralogy (he was a keen geologist), crystallography, philology, pathology, and botany as well as chemistry. Thomson said Dr. Wollaston s knowledge was more varied, and his taste less exclusive than any other philosopher of his time, except Mr. Cavendish. ... 

Electromagnetics Gamma-Ray Astronomy In-ERARED Astronomy Optical Dieeraction Ultraviolet Space Astronomy... 

In astronomy, we are interested in the optical effects of the turbulence. A wave with complex amplitude U(x) = exp[ irefractive index, resulting in a random phase structure by the time it reaches the telescope pupil. If the turbulence is weak enough, the effect of the aberrations can be approximated by summing their phase along a path (the weak phase screen approximation), then the covariance of the complex amplitude at the telescope can be shown to be... 

The performance of an optical imaging system is quantified by a point-spread function (PSF) or a transfer function. In astronomy we image spatially incoherent objects, so it is the intensity point-spread function that is used. The image is given by a convolution of the object 0, r]) with the PSF... 

In the 1970 s Pierre Connes in France made a 4.2 m segmented mirror telescope for infrared astronomy (Fig. 4). It was fully steerable, and active. Unfortunately, the optical quality was too low to be useful for astronomy. 

Keywords Micro-optics, MOEMS, multi-object spectroscopy, adaptive optics, astronomi-... 

A strong collaboration between micro-optics and astronomy will certainly lead to reach the best scientific return for the lowest cost in next generation astronomical instrumentation for ground-based and space telescopes. 

Although astronomy is accustomed to the detection of a few photons per pixel, the electric charge of a few electrons is extremely small. A critical part of the design of a focal plane array is the amplifier which converts the small amount of charge in each pixel into a signal that can be transmitted off the detector. The amplifier in an optical or infrared detectors is typically a field effect transistor (FET), a solid state structure which allows a very small amount... 

P. Amico and J. W. Beletic eds., Optical Detectors for Astronomy II, state-of-the-art at the turn of the millenium, ASSL Series, Kluwer Academic Publisher, Dordrecht, 2000. 

Courtgs, G. 1982, in Instrumentation for Astronomy with Large Optical Telescope, Proc. lAU Colloq 67, Astrophysics and Space Science Library 92, pl23. ed. Humphries, C.M., Dordrecht, Reidel Dubbeldam, C.M., et al., 2000, SPIE 4008, 1181... 

Roddier, F. (ed.), 1991, Adaptive Optics in Astronomy, Cambridge Univ. Press Rousset, 1992, Adaptive Optics for Astronomy, ed. Alloin, D.M., Mariotti, J.-M., NATO ASI 423, 115, Kluwer Academic Publ. 

Dainty, C., Ageorges, N., 2000, Laser Guide Star Adaptive Optics for Astronomy, NATO/ASl 551... 

S., Ott, T., Davies, R., Eckart, A., 1999, in Astronomy with Adaptive Optics -Present Results and Future Programs, ESO and OSA, 333... 

Perrin, G., Lai, O., Fena, P, Coude du Foresto, V., 2000, Fibered large interferometer on top of Mauna Kea GHANA, the optical Hawaiian array for nanoradian astronomy, SPIE 4006, 708... 

Abstract Optical Parametric Oscillators provide a very efficient source of tunable coherent radiation. The principle of different kinds of OPOs are described. OPOs are used in astronomy for Laser Guide Star systems, and they may be used for other nonlinear optics applications in astrophysics, such as frequency conversion or parametric amplification. 

We investigate here whether coherent detection of optical waves issued from celestrial sources can be processed in a way similar to radio astronomy (Fig. 1). 

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