Abstract: The results of the interdisciplinary project "Sphaera octava" will be presented. Its goal was to study selected Latin treatises crucial for the development of astronomy from Late Antiquity through Middle Ages up to Early Modern Times. A particular attention was devoted to tracing the evolution of ideas on the fixed stars starting from the ancient description of constellations, through cataloging of stellar positions and magnitudes up to the breaking of the "eighth sphere" by telescopic observations. The texts like Hyginus's "Astronomy", Al Sufi's "Catalogue of stars", Galilei's "Sidereus nuncius" and others were translated into Czech and commented. In addition, the unique precession celestial globe from the collection of Nicolaus Cusanus was investigated.

Abstract: Traditionally, hot massive stars have been studied under the assumption that their winds are homogeneous and stationary. However, observations with the newest instruments, together with progress in model calculations, ultimately dictate a cardinal change of this paradigm: stellar winds are highly inhomogeneous. In this talk I'll present the new sophisticated 3-D models of radiation transfer in inhomogeneous expanding media which we developed in order to elucidate the physics of stellar winds and improve classical empiric mass-loss rate diagnostics. I'll also present applications of these new techniques to multi-wavelength observations of hot massive stars which yield consistent and robust stellar wind parameters.

Abstract: We will present results of a recent study of a hot prominence embedded in the core of large Coronal Mass Ejection (CME) as was observed by the SOHO satellite. Physical parameters of the prominence plasma were derived using SOHO/UVCS hydrogen Lα and Lβ line spectra and SOHO/LASCO visible-light images. We developed a diagnostic tool based on the non-LTE radiative transfer code which accounts for large velocities of the moving CME. We will also briefly discuss a complementary diagnostics based on the observed CIII line. The methods developed in this work will serve for future data analysis from the METIS coronagraph on board the Solar Orbiter mission (ESA).

Abstract: Every asteroid pair consists of two components that share practically the same heliocentric orbit though they are not tied together any more. Shortly after their discovery 8 years ago many general properties of asteroid pairs were revealed (e.g. typical sizes, shapes, mass ratios of their components, correlation of the spin rate of primaries with the mass ratio, prevailing formation mechanism by rotational fission). Our knowledge about that population extended with additional data. Although initial results have been confirmed or nailed down, some details remain open. For example, how exactly asteroid pairs form? How frequently asteroid pairs form? With the estimated ages of known pairs (typically of the order of 10 4 to 10 6 years) and large uncertainties, answers to the questions above can hardly be found. It is believed that the study of the youngest pairs could shed some light on the problem. Recently, we have found a few candidates for very young asteroid pairs – perhaps younger than 10 4 years. But even their age determination is not easy. Large uncertainty or even ambiguity are caused due to several reasons, such as extremely slow separation velocity of pair components, components can repeatedly closely encounter each other several times, some of their physical properties, which are critical for orbital evolution, are usually unknown.