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Catadioptric systems of Argunov, Popov and Klevcov
Rail, Zdeněk ; Jareš, Daniel ; Lédl, Vít
This paper deals with two-mirror systems of Argunov, Popov and Klevcov which use meniscus correctors in convergent beam of light placed near their secondaries. These systems make possible to construct of highly aberration corrected devices. Several telescopes of this type are producted commercialy and belong to the best corrected catadioptric systems.
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The Corrector of Volosov
Rail, Zdeněk ; Jareš, Daniel ; Lédl, Vít
Soon after discovery of meniscus telescope of Maksutov optical properties of doublet corrector was researched. Doublet was placed into parallel light beam in front of common optical system. Afocal corrector composed of two thin lenses of the same glass enables to correct optical aberrations of many systems and to reach radical improvement of their imaging properties. Compared to Schmidt plate doublet corrector possesses only spherical surfaces and its manufacturing tolerances are much freer than meniscus of Maksutov. Derivation of main equations was performed by Volosov, Galpern and Grebenshchikova in 1943. Our paper deals with optical aberrations of the system consisting of common aspherical mirror and corrector of Volosov. These systems are less known among opticians and astronomers but enable construction of fast cameras and telescopes.
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Měření piezoelektrického aktuátoru pro posun textilií metodou digitální holografie s frekvenčně posunutou referenční vlnou
Lédl, Vít ; Václavík, J. ; Rusín, L. ; Erhart, J. ; Kopecký, V.
The actuator for moving the fabric is under development. It is necessary to characterize its properties. Time average holographic interferometry seems to be suitable tool for this purpose. However it is impossible with standard technique to resolve amplitudes in tens of microns, which are characteristic for the operation of the actuator. Time average holographic interferometry with frequency shifted reference wave has to be applied to solve this problem. Few expositions of the vibrating actuator have been captured with different frequency shift of the reference wave. Bessel functions obtained from these interferograms were fitted together by the automated software. The shape and the amplitude of the movement were successfully measured in whole area of actuator.
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Prospects of digital holographic interferometry in heat transfer measurement
Doleček, R. ; Lédl, Vít ; Kopecký, V. ; Psota, P. ; Václavík, Jan ; Vít, Tomáš
In the measurement of heat transfer problem, a holographic interferometry (HI) is often used mainly because of its unique properties and very high adaptability to different sort of problems under investigation. Although in the area of vibration or deformation measurement of solid body the standard HI is replaced massively by digital holography in the case of refractive index distribution the situation is quite opposite. In this paper we present two different types of digital holographic interferometers. The interferometers with different sensitivities have been build and successfully tested.
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Thermoakustic prime Mover – demonstrace a první experimenty
Chen, Y.-C. ; Vít, T. ; Lédl, Vít ; Kordík, Jozef ; Maršík, František ; Wang, A. B. ; Doleček, R. ; Trávníček, Zdeněk
The present paper focuses on an experimental investigation of the thermoacoustic prime mover (sound generator), which was designed with the quarter-wave resonant tube. The working fluid was air under the barometric pressure. This study proves function of the prime mover, and demonstrates variety of experimental methods for experimental investigation of the thermoacoustics: acoustic measurements (the resonant frequency, power spectrum, and sound pressure level), temperature measurement (temperatures along the resonant tube, namely near the thermoacoustic stack), hot-wire measurement (oscillation velocities and displacements), and optical experiments by the holographic interferometry.
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Aplication of matlab for textile ingeneers education
Salačová, J. ; Lédl, Vít
Students are prepared in the frame of MSc. studies in such a way that they can solve the most demanding tasks in the studying subject as textile quality management, textile testing, textile marketing, methods of thermal analysis or data exploratory analysis. Named subjects are requiring solving of complex mathematic tasks or evaluation of measured data. Student are supposed to be able to research properties of textile structures and textile materials. With upcoming innovation in textile material engineering (such as nanofibres, nanotechnology, new types of the technical textile, intelligent textile) there is necessary improvement in the education process. Innovation is focused on extended use of MATLAB for automatic defectoscopy and generally on textile evaluation. It is connected mainly to semiautomatic processing of measured dat, the possibilities the data visualization, searching of textile structures defects, defects classification or selected tasks of analytic geometry.
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Schmidt-Cassegrain Telescopes
Jareš, Daniel ; Lédl, Vít ; Rail, Zdeněk
This paper describes analysis of residual aberrations of Schmidt-Cassegrain telescopes (SCT). Though SCTs have been produced for 30 years, problem of imaging properties is only rarely discussed. At first we have performed measurement of optical parameters of several commercially produced SCT telescopes of Meade, Celestron and Carl Zeiss Jena, then we have used measured data to construct the models of these system with the help of Zemax program and evaluate residual aberrations. We have found that it is possible to radically improve these systems by changing entry data.
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Imaging system for spectrograph with multichanell Šolc filter
Rail, Zdeněk ; Lédl, Vít ; Jareš, Daniel
Solving the problem of solar spectrograph telescope,we have made research of possible imaging systems for spectrograph with multichanell Šolc filter.We have decided to use off-axis unobstructed Maksutov telescope,which is able to meet our demands for constant solar image scale in wavelenght within 380 to 760 nm.This telescope provides good image contrast similar to apochromatic objective lens uses only classical materials. Diameter of the telescope is 140 mm,focal length is 2000 mm.
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