National Repository of Grey Literature 25 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Astronomical grounds of calendars in different historical periods and cultures
Hrůšová, Lucie ; Šolc, Martin (advisor) ; Wolf, Marek (referee)
The main goal of this work is to describe calendars of various countries, and that both calendars, which are used until these days, and calendars of perished civilizations or calendars, which were abandoned by their users because during ages they had preferred another calendar. This work is for everyone, who would like to be informed, how our calendar was originated, why he contains some things which are illogical from our point of view such as the irregularity of the length of months. It also tries to show the way how the calendars were created, how they were refinement, but also that the calendar we use most, the Gregorian calendar, is not still perfect. First chapter wants to explain to reader, what is the lunar, solar and lunisolar calendar. In second chapter are described calendars of the eldest known Mediterranean civilizations in the context of antique literary creation. Third chapter is dedicated to the world's most widespread Gregorian calendar, the circumstances of his rise by correcting the Julian calendar, about his acceptance in world and about the lunar point in this otherwise solar calendar, namely the calculation of Easter. The fourth chapter is dealing with the newer calendars, which was tried to enter into force by revolutionary minded persons. And the last, the fifth, chapter is...
A new spectroscopic study of the eclipsing binary V1143 Cyg
Jonák, Juraj ; Harmanec, Petr (advisor) ; Wolf, Marek (referee)
Using multiple red spectra of the eclipsing binary V1143 Cyg obtained between the years 2015 and 2017 at the Observatory of Ondřejov and in 2008 and 2009 at the Lick observatory in USA, we calculated a more recent orbital solution using the method of Fourier spectra disentangling. These new data, in addition to previous spectroscopic and photometric measurements, span an observation period of almost a hundred years. Since this binary star is remarkable due to its high orbital excentricity, along with classical, a significant relativistic apsidal motion is present. Using the software PHOEBE and available data we calculated the value of the total apsidal motion as 9,8(3).10−5 deg.d−1 , which is in good agreement with previous works. 1
Study of connection between period changes and spectral type in eclipsing binaries
Vyhnálková, Veronika ; Zasche, Petr (advisor) ; Wolf, Marek (referee)
Main aim was to study whether there is a correlation between the changes in the period of the eclipsing binary stars and the spectral type of their secondary components. In the course of this thesis the character of period changes based on O-C diagrams is studied. Obtaining necessary data, several diagrams were constructed, namely the dependence of the mass ratio of both components (or period) for the effective temperature of the secondary, and another for various star type and lenght of measurement. From these diagrams the absence of alterning period change of the binaries with hot secondary was not proved, but it is indicated the shift of temperature of secondaries for binaries with increase (decrease) period to higher (lower) values. Also it was showed that monotone period changes are approximately twice more frequent for β Lyrae and W UMa-type stars than for Algols.
Flare stars
Kára, Jan ; Wolf, Marek (advisor) ; Švanda, Michal (referee)
The works deals with the study of the flare stars, which is a group of stars for which sudden brightening can be observed. The work focuses on a star GJ 3236, which is a low-mass eclipsing binary and on which numerous flares have been observed. For the analysis of this system spectroscopic and photometric data were used, which were obtained at various observatories. Parameters of the binary system have been determined by analysing spectroscopic and photometric data with the program PHOEBE. A total of 241 flares have been detected in the photometric data and for 190 flares, which light curves were not affected by eclipses, released energies were estimated. The set of flares was used for the study of stellar activity of the binary. The energy distribution of observed flares is similar to the flares observed on other flare stars and also on the Sun. This suggests, that the flare mechanism is the same for these stars.
Recruitment in a non-profit organization.
Steklá, Veronika ; Stříteský, Marek (advisor) ; Wolf, Marek (referee)
The main objective of this thesis is to create a proposal for improving recruitment campaign for AIESEC Prague based on research. The thesis is divided into two parts, a theoretical and a practical part. The theoretical part defines necessary terminology. The introduction of the practical part explains the fundamentals and the structure of AIESEC, both from an international perspective and Czech republic perspective. The practical part continues with an evaluation of a survey, which consists of three questionnaires. The evaluation is divided into six individual subchapters. The results of the survey are complemented by a list of other student organisations that are potential competitors. This is followed with evaluation of AIESECs position in the student organisations market in terms of strenghts, weaknesses, potential opportuities and threats. The conclusion summarizes and proposes further improvements to the recruitment proces.
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)
Pulsating components in binaries
Korda, David ; Zasche, Petr (advisor) ; Wolf, Marek (referee)
In the beginning there are introduced the binaries and pulsating stars. The main aim of the present work was the study of Delta Scuti stars within the eclipsing binaries. In particular, observing the stellar system V389 Cas at Ondrejov observatory, reduction of the CCD images with the program MuniWin, and analysis of the light curve with program Phoebe. From the residuals of the light curve there were studied the pulsations by the program Period04, resulting in its pulsational period. The relation between both periods - orbital and pulsational - was studied by means of the already known systems, including the theoretical relation and location of the star V389 Cas in the period-period diagram. 1
Selected gravitational effects in the Universe
Franc, Tomáš ; Wolf, Marek (advisor) ; Randa, Miroslav (referee) ; Štefl, Vladimír (referee)
Title: Selected gravitational effects in the Universe Author: Mgr. Tomáš Franc Department: Astronomical Institute of Charles University Supervisor: doc. RNDr. Marek Wolf, CSc., Astronomical Institute of Charles University Abstract: In this Thesis we have given an overview of tidal phenomena with their explanations and also explained the gravitational assist with examples of its use. We have created many pictures and 17 animations for better understanding of these topics. This part of the Thesis is focused on high school students and their teachers, it can be used by teachers for their inspiration for lessons, or students and more generally people interested in these topics can read this part as a study text. The main part of the Thesis is the result of research conducted on 13 high schools in the Czech Republic. 800 students took part in the research; its purpose was to find out students' knowledge of tidal phenomena and the gravitational assist. The research was carried out in the form of questionnaires. Keywords: gravity, tidal phenomena, gravitational assist, pedagogical research

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2 Wolf, Martin
2 Wolf, Michal
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