On the Astron UV Space Mission Data

The Soviet UV space mission Astron, launched in 1983, had been operational for eight years as the largest ultraviolet space telescope during its lifetime. Astron provided a lot of observational material for various types of astrophysical objects, but unfortunately these data were not widely available and, as a result, unduly forgotten. Here we present some results of our comparison of the Astron data to the modern UV stellar data, such as the NGSL spectral library, discuss the precision and accuracy achieved with Astron, and make some conclusions on potential application areas of these data.

Carl Friedrich Gauss – General Theory of Terrestrial Magnetism – a revised translation of the German text

This is a translation of the Allgemeine Theorie des Erdmagnetismus published by Carl Friedrich Gauss in 1839 in the Resultate aus den Beobachtungen des Magnetischen Vereins im Jahre 1838. The current translation is based on an earlier translation by Elizabeth Juliana Sabine published in 1841. This earlier translation has been revised, corrected, and extended. Numerous biographical comments on the scientists named in the original text have been added as well as further information on the observational material used by Carl Friedrich Gauss. An attempt is made to provide a readable text to a wider scientific community, a text laying the foundation of today's understanding of planetary magnetic fields.

The Meanings of Practices for Energy Consumption – a Comparison of Homes and Workplaces

We examine how building and appliance technologies relate to their use by occupants through practices at home and at work. The aim is to analyse how practices are influenced by buildings and other technologies and by social requirements and to add to ongoing research on how to contribute to a transition to more sustainable everyday practices. Interview, quantitative and observational material are used to compare experiences of occupying and using two different types of buildings, passive housing and large modern research laboratories. We apply the practice theory approach. The passive house case showed that the main project of a liveable, low-impact new building was on a fairly manageable scale, with a viable design and occupants who were prepared to adapt to it. The research lab study showed, however, that the configuration of unsustainable technologies and practices can occur at the design stage, and that most actors had very limited room for manoeuvre.

Internal Motions of Trapezium Systems

The separations of the various components of 44 trapezia as a function of time are studied, taking advantage of many new, high precision observations for these objects. A previous study revealed that some systems have components moving with velocities larger than the escape velocity (Allen et al.1974). The present work updates our previous study, extending the observations by about 30 years, and thus allowing an improved determination of the relative transverse motions of the components. The analysis of the new data confirms the conclusions we reached in our previous work: most of the trapezia show the internal motions expected for bound, virialized small clusters, but a few have escaping components. The available observational material lends support to the concept that trapezia are unstable systems with lifetimes of the order of a few million years.

Direct detection of multiple periods in variable stars

In some observational data sets of variable stars, multiperiodicity was not always recognized as such, and only became apparent when other observational material became available. In other cases, consecutive prewhitening starting with the obviously most significant frequency could lead to a wrong multifrequency solution. A few examples illustrating this are given. Searching directly for a multifrequency solution can often remedy this. Examples are given and the results of applying this technique to a large set of Hipparcos photometric data are communicated. An overview of the multiple periodicities found in β Cephei stars and SPB stars is reported in detail.

Large-Scale Errors In CCD Photometry of M67

The accuracy of new CCD photometry in the Vilnius system of the M67 cluster is analyzed. The observational material is obtained during six observing runs in 1994-2001 with the 1 meter telescope of the USNO Flagstaff Station. The main task was to establish CCD standards of high accuracy and to eliminate large-scale errors from our CCD photometry. We compare our results with the published CCD photometric data in other photometric systems. The comparison reveals considerable systematic errors in some datasets.

Luminosity Calibrations with Hipparcos: Theoretical Point of View

Hipparcos provided us with valuable observational material that can be used to anchor more firmly the Galactic and extragalactic distance scales. A calibration which is applicable to all stars must allow for differences in chemical composition and other properties, which may require the use of theoretical models. I discuss some difficulties encountered in the calibration procedure that are related (1) to the determinations of stellar temperatures, luminosities and chemical compositions, (2) to remaining weaknesses of theoretical stellar models, and (3) to the transformations of the model outputs from the (Mbol,Teff) plane into any colour-magnitude or colour-colour diagram.

The analysis of total solar eclipse observations on August 11th, 1999 in Kikinda

Because of poor meteorological conditions, the obtained observational material has not an even distribution in time. Therefore a special method was devised for treating this material. Using this method the durations of total and partial phases of this eclipse were established.

Joint Discussion 8: Stellar Evolution in Real Time, Part III: Implied Evidences

It is inevitable that understanding of some indicators of stellar evolution is not so definite as we could wish. This can be equally true of observational material and of the beginning and intermediate stages of theoretical development. Even though these matters may be arguable and untidy, they are not negligible and, in fact, represent obvious recognized opportunities for the near future. It is possible that these matters are really the most valuable consequence of the meeting. Subject matter of this kind was presented at the JD8, in both invited and contributed forms, and their summaries follow here in the same approximation to stellar evolution stages that characterized Part II.