The Work of the BAV
An Overview of the technical work of the Bundesdeutsche Arbeitsgemeinschaft für Veränderliche Sterne e. V. (BAV)
History of the BAV
The "Bundesdeutsche Arbeitsgemeinschaft für Veränderliche Sterne" was founded 1950 by amateur astronomers at the Archenhold Observatory in Berlin-Treptow. The intention was - and still is - to support amateurs in the systematic observation of variable stars.
The observations are published and therefore may give professionals additional information for their work. The observation programs of the BAV are composed in cooperation with professionals in regard to their research foci.
Observation of Variable Stars
Observation GoalsEspecially long-term observations are highly valuable and enable us to deduce the physical characteristics of variable stars. From measurements of brightness variations the times of maximum or minimum are derived. Moreover, the elements of brightness variations of specific stars are derived and new variables are systematically sought and classified.
Observation TechniquesUntil the 1980s visual observations dominated. Later the light-electric photometry was established, while nowadays the CCD-technology prevails. Today more than 2,000 maxima and mimima are observed per year.
The Observation Programs of the BAVThe following variable types are systematically observed: Eclipsing binaries, short-period pulsating stars (RR Lyrae, delta Scuti and delta Cephei stars), long-period pulsating stars (Mira stars, RV-Tauri and semi-regular stars), eruptive and cataclysmic stars.
The Publication of Observation Results in the BAV MitteilungenThe observation results are communicated in the BAV Mitteilungen. Between 1950 and 1981 these were mainly published in the Astronomische Nachrichten, since then primarily in the Information Bulletin on Variable Stars (IBVS) of the commissions 27 and 42 of the IAU. Until 2010 more than 200 BAV Mitteilungen were published with more than 43,000 observed maxima and minima.
Collaboration with Professional AstronomersThe professionals are interested in the collaboration with amateurs as long as they can rely on high quality CCD-results which are typical for the BAV observations. At the biennial BAV conventions professionals do not only present their work, but also express wishes for support by amateurs.
The Lichtenknecker-Database of the BAV
The observations were collected from many worldwide available literature sources. In our understanding they are nearly complete, especially with regard to historic observations. The search covered more than 200 publications and periodicals. The criteria for including stars in the database are a brightness of more than 13 mag in normal light and a declination north of -20 degree. There is no limit for the amplitude or period.
A comprehensive description of the work of the BAV is available through one of the following links available.
Berlin, September 21st, 2010; Joachim Hübscher