ISBN-13: 9786139872367 / Angielski / Miękka / 2018 / 136 str.
One of the most recent problem in astronomy and astrophysics is to investigate the evolution of the universe and the formation of it's component as well. This work will make a shad light on one of the most vital issues in this field which is variable stars and Binary systems. A general outline of its history has been introduced by the author. The different techniques of its optical observations have been also presented. This followed by a detailed discussion of three systems observed using CCD camera attached with Kottamia Astronomical Observatory.