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Analysis and Suppression of Noise in Astronomical Video
Švihlík, J. ; Fliegel, K. ; Koten, Pavel ; Jerhotova, E. ; Vítek, S. ; Páta, P.
This paper is devoted to noise suppression in systems for double station observation of meteors, nowadays known as MAIA (Meteor Automatic Imager and Analyzer). The noise analysis based on acquisition of testing video sequences at different lighting conditions and their statistical evaluation were described in our previous paper The measurement showed that the type of noise generated by the system is signal-independent in a certain illumination range. The noise and image models in the wavelet domain are based on the Generalized Laplacian Model (GLM) and it is the most convenient to estimate the model parameters using the moment method. Furthermore, the noise component may be modeled by the GLM also in the space domain. Overall, we verified that the GLM allows for modeling various types of probability density functions. In the final section of this paper, the performance of the proposed advanced de noising algorithm is verified on the real data, which were acquired in the Astronomical Institute.
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New model of precession, valid in time interval 400 thousand years
Vondrák, Jan
New model of precession, expressed in terms of long-periodic trigonometric functions of time is developed, based on numerical integration of motions of the Solar system bodies. Its validity is +/- 200 thousand years from the basic epoch J2000, with the accuracy below one milliarcsecond in the central part and gradually decreasing to a few arcminutes towards both ends of the interval of validity.
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Kosmologie, čísla a Platonova duše světa
Rajchl, Jaroslav
Současná kosmologie se vyznačuje velkým množstvím nejrůznějších modelů. Bližší pohled ukazuje, že všechny oplývají určitým typem dualnosti, a sice propojením dynamické a formativní podoby, jejichž společným zdrojem je známý Velký třesk (BB). Abychom zpřehlednili onen složitý obraz, vybrali jsme jako určitý sjednocující symbol tzv. Platonův model duše světa (PDS), který vychází z Pythagorova postřehu, že analogickou dualností se vyznačují i čísla.
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Shell-Like Structures in the ISM: Observation Versus Simulations
Sidorin, Vojtěch ; Palouš, Jan
The interstellar medium in galaxies is a turbulent environment with a plethora of holes, bubbles and shells. All these shell-like structures are thought to be closely related to the formation, evolution and death of stars. In most cases, they are likely created by the winds of OB stars and supernovae. The material collected along the borders of shells may fragment, become unstable under its own gravity, and create a new generation of stars. This is a variant of triggered star formation referred to as the collect-and-collapse scenario. The aim of our research is to compare numerical simulations of shell-like structures to observations and to search for and investigate regions of triggered star formation in the Milky Way.
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