The All Sky Automated Survey. Catalog of about 3800 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 square degrees were monitored each clear night in the I-band resulting in the ASAS Photometric I-band Catalog containing over 5×107 individual measurements. Nightly monitoring of over 100 standard stars confirms that most of our data remains within σI=0.03 mag of the standard I system. Search for the stars varying on the time scales longer than a day revealed about 3800 variable stars (mostly irregular, pulsating and binaries) brighter than 13 mag. Only 630 of them are known or suspected variables included in the GCVS (Kholopov 1985). Among the stars brighter than I≈7.5 (which are saturated on our frames) we have found about 50 variables (12 are in the GCVS, 6 others in the Hipparcos catalog. Because of the large volume of 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/