The All Sky Automated Survey: A Catalog of almost 3900 variable stars

Results of the first two years of observations using the All Sky Automated Survey prototype camera are presented. More than 140 000 stars in 50 Selected Fields covering 300 sq. degrees were monitored each clear night in the I-band resulting in the ASAS Photometric I-band Catalog containing over 50 x 10^6 individual measurements. Nightly monitoring over 100 standard stars confirms that most of our data remains within sigma_I=0.03 of the standard I system. Search for the stars varying on the time scales longer than a few days revealed almost 4000 variables (mostly irregular, pulsating and binaries) brighter than 13 mag. Only 155 of them are known variables included in GCVS, 56 were observed by Hipparcos satellite (46 were marked as variable). Among the stars brighter than I ~ 7.5 (which are saturated on our frames) we have found about 50 variables (12 are in GCVS, 6 other in Hipparcos (Perryman etal 1997) catalog). Because of the large volume of the data we present here only selected tables and light-curves, but the complete ASAS Catalog of Variable Stars (currently divided into Periodic and Miscellaneous sections) and all photometric data are available on the Internet http://www.astrouw.edu.pl/~gp/asas/asas.html or http://archive.princeton.edu/~asas