|
|
Distance to the Magellanic clouds
Kulich, Matúš ; Zasche, Petr (advisor) ; Korčáková, Daniela (referee)
Twelve eclipsing binary systems from the region of the Large Magellanic Cloud have been studied in this thesis in order to calculate the distance. The photometric data come from the OGLE survey carried out at the Las Campanas Observatory in Chile and the spectroscopic data come from other papers where they had already been partially ana- lyzed for other purposes. From these data, the light curves and the radial velocity curves of these systems have been constructed and analyzed using the PHOEBE soft- ware, in which the physical parameters and the absolute magnitudes of their individual components have been determined by the method of synthetic curves. By comparing them to the observed apparent magnitudes in I-band deduced from the light curves and taking into account the bolometric corrections and the V-I indices, the distance modu- lus of the Large Magellanic Cloud could be determined to be 18.59 ± 0.4 mag, which fairly corresponds to the quite familiar results determined by using this and other meth- ods in various research papers. However, in order to determine the distance modulus more accurately, it would be necessary to use accurate, much more complex models of stellar atmospheres and not simply rely on the general relations of the main-se- quence stellar parameters, which exhibit quite a large variance.
|
|
|
The light curves of eclipsing binaries
Korda, David ; Zasche, Petr (advisor)
New CCD photometric observations of ten short-period LMB (Low Mass Binaries) were carried out. Data were obtained using 65 cm telescope in Ondrejov in the filters I, R and V from 2014 to 2016. Light curves were analysed using the program PHOEBE. The obtained masses and radii of the stars were compared with the theoretical mass-radii relation. There arises that the short-period binaries have the radii of about 4 % larger than the theoretical prediction from the stellar evolution models. 1
|
|
|
CCD photometry of variable objects in nearby galaxies
Kára, Jan ; Wolf, Marek (advisor) ; Zasche, Petr (referee)
The work concerns the study of variable stars in the Small Magellanic Cloud with use of time series of photometric images of star field NGC 330, which were obtained by the 1,54-m Danish telescope at the observatory La Silla in Chile during years 2012 - 2016. The aim of this work is to produce light curves of variable stars a to determine their period of variability assuming the variations are periodical. For some stars data from earlier published papers were used, which led to the coverage of longer period of time and therefore to the improvement of the accuracy of the period determination. The work lists summary of some of the types of variable stars and of mechanisms causing their variability. The work focus mainly on cepheids, which can be used to determine distances in the Universe thanks to the relation between their absolute magnitude and period of pulsation.
|
|
|
The light curves of eclipsing binaries
Korda, David ; Zasche, Petr (advisor) ; Wolf, Marek (referee)
New CCD photometric observations of ten short-period LMB (Low Mass Binaries) were carried out. Data were obtained using 65 cm telescope in Ondřejov in the filters I, R and V from 2014 to 2016. Light curves were analysed using the program PHOEBE. The obtained masses and radii of the stars were compared with the theoretical mass-radii relation. There arises that the short-period binaries have the radii of about 4 % larger than the theoretical prediction from the stellar evolution models. Powered by TCPDF (www.tcpdf.org)
|
|
|
The light-curve solution of an eclipsing binary
Procházka, Ondřej ; Zasche, Petr (advisor) ; Wolf, Marek (referee)
The main aim of this work was the first detailed analysis of an eclipsing binary system V641 Aur. The complete light curve of this binary was obtained in three photometric filters, which were analyzed with the program PHOEBE. It is a double star with the orbital period of about 0.50487 day, whose both components are rather similar. Their individual spectral types are probably F6 and F8 (according to the temperatures), or F6 and F6 (as derived from masses). Both are orbiting on a circular orbit and despite their short period the system is a detached one and both components are still located on the main sequence. Moreover, thanks to the asymmetry of the light curve there was discovered a spot on the surface of the primary component, and the third light was not detected. For more detailed analysis higher accuracy of photometry and spectroscopy data are required.
|
|
|
Comparison of optical methods for characterization of glass mosaic weathering
Kocour, Vladimír ; Petráňová, Veronika ; Valach, Jaroslav
The work presented in this paper is a part of research project supported by Ministry of Culture and devoted to conservation of precious mosaic of 'Last Judgement' on St. Vitus Cathedral in Prague. The aim of the project is to enhance external protective polymeric coating on glass tesserae of mosaic and also to develop optical method for assessment of coating’s surface conditions. The paper concentrates on comparison of various methods for surface evaluation assesses their advantages and disadvantages and also discusses their suitability for long term monitoring of coating state, namely reflectometry, scanning probe microscopy, nanoindentation, white-light interferometry, and scanning electron microscopy. It is found that white-light interferometry and reflectometry methods are the most suitable ones for monitoring purposes.
|
|
|
Map of lighting in GIS
Otáhal, Miroslav ; Bubník, Karel (referee) ; Rozman, Jiří (advisor)
Bachelor thesis is about theory of outdoor illuminating system in area of public streets and roads. Thesis is divided into the two parts. First part describe basic terms of photometry and measure technique along with hygienic regulation of ČSN EN 13201 standard. In this part is also a describable of geographic information system ArcGIS, which can be used in practice part. Second part is about practice of measure illumination of standard ČSN EN 13201 specification. This measure was performed in different parts of Brumovice village (South of Moravia). These results were compared by hygienic regulation of ČSN EN 13201 specification. The final result of this research is a map of public outdoor illuminating system. In this map there are marked parts, which fall within convenient of good and bad answers, according ČSN EN 13201 specification standard.
|
|
|
Measurement of operating room lights quality
Rovná, Tereza ; Potočňák, Tomáš (referee) ; Harabiš, Vratislav (advisor)
This thesis is focused on measuring the quality of lighting in operating rooms. Operating lights are very demanding in terms of quality requirements for each parameter, so it is important to specify exactly these parameters and check them regurarly. To measure the quality of the light source, was used a special kit from Maquet. Measurement procedure was not as accurate as it was for operating lighting need, therefore, this work includes a proposal to improve the measurement of quality lighting in operating theaters. In cooperation with University Hospital Brno Bohunice University Hospital Motol and the company Maquet measured nine operating lights, each light were compared in terms of parameters such as maximum light intensity, light distribution in the surgical field. In each category were selected several lighting, which reached the best results. The various parameters were compared with values declared by the manufacturer.
|
|
|
Scene Ilumination by Photon Mapping Method
Hübner, Lukáš ; Španěl, Michal (referee) ; Kršek, Přemysl (advisor)
This thesis deals with the estimation of global illumination of a~scene. Global illumination is expressed as a~physical simulation in connection with illumination methods used in current computer graphics. In the practical part there is expressed an implementation of global illumination estimation using photon maps.
|
|
|
Unconventional Methods of Measurement in Photometry
Škoda, Jan ; Sokanský, Karel (referee) ; Gašparovský,, Dionýz (referee) ; Baxant, Petr (advisor)
This thesis deals with an unconventional possibility of measuring photometric values and the work is based on analysis of luminance made by commercially available digital photo camera. In the first part is represent an overview of current methods for measuring the photometry. You also can see the basic photometric values and required instrumentation needed to measure them. The focus of the work is concentrated on the description of the problems associated with setting the correct luminance of digital photography. It describes the dependency and correction procedures for calculating fixed luminance ratios of the individual images. The last part of this thesis is devoted to the possible use in practice, especially in the analysis of luminance of objects, luminaires and light sources. It also deals with an alternative description of luminaire and light sources to replace the luminous intensity curve etc.
|
guest ::
