Our conference - opening today - has two aims in view: first, to commemorate some milestones in the development of the studies of close binary systems whose anniversaries fall in these years, as well as to take stock of our present knowledge accumulated through­ out preceding decades, in order to consider where do we go from here. This summer, 310 years will have elapsed since the first ec­ lipsing binary - Algol - was discovered in Bologna by Geminiano Montanari (1633-1687) to be a variable star; and 198 years have gone by since John Goodricke of York (1764-1786) established the fact that Algol's light changes were periodic. Moreover, it is al­ most exactly (to a month) now 100 years since Edward Charles Pickering (1846-1919) of Harvard Observatory in the United States took the first steps towards the development of systematic methods of analysis of the light changes of Algol and related systems - a topic which will constitute the major part of the programme of our present conference. The three dates recalled above illustrate that the discoverers of such celestial objects and observers of their light changes have been systematically ahead of the theoreticians endea­ vouring to understand the significance of the observed data by de­ cades and centuries in the past - a fact which, incidentally, con­ tinues to hold good (albeit with a diminishing lead-time) up to the present.

Inhalt

I: Light Changes of Eclipsing Variables and their Analysis.- The Royal Road of Eclipses.- Error Analysis of the Elements of an Eclipsing Binary System in Frequency Domain.- A Simple Synthesis Method for Solving the Elements of Well-Detached Eclipsing Systems.- The Uniqueness Criterion: The Analysis of Eclipsing Binary Light Curves.- Light Curve Analysis for the Basic Spherical-Model of Eclipsing Variables in the Frequency Domain.- A Computer Program for the Frequency-Domain Analysis of the Light Curves of Eclipsing Variables.- A Study of Special Functions in the Theory of Eclipsing Binary Systems.- Photometric Perturbations of Close Binaries in the Frequency-Domain.- An Analysis of the Light Changes of W UMa-type Systems in the Frequency Domain.- II: Eclipsing Variables: Photometric Observations.- Data Acquisition in Astronomical Photoelectric Photometry.- Detection of Close Binary Systems by Means of Lunar Occultations.- Progress and Problems in RS CVn Star Research.- Observations of RS CVn-type Binary Stars.- The System RT And and the Transit/Occultation Question.- The Short-Period Group of Eclipsing Binaries with Properties Similar to the Classical RS CVn Group.- Photoelectric Study of the RS CVn-type Binary TY Pyxidis.- BV Photometry of Selected RS CVn-type Eclipsing Binaries.- Observations and Analysis of UU Sge.- The Light and Period Variations of OO Aquilae.- Photoelectric Observations of Eclipsing Binary Systems at Kryonerion Observatory, Greece.- Stepanian's Star.- Note on the Eclipsing Binary AW Ursae Maioris.- III: Spectroscopic Studies of Close Binary Systems.- Ultraviolet Spectra of Interacting Binaries.- U Cephei Viewed from Maratea.- Certain Aspects of the Problem of Mass Transfer in Semi-Detached Binaries.- The Study of Apsidal Motion in Eclipsing Binaries.- Temperature Determination of Exciting Stars in Highly Excited Planetary Nebulae and Symbiotic Stars.- Gas Streams in Close Binary Systems.- Name Index.- Index of Individual Eclipsing Variables.