Direct distances to nearby galaxies using detached eclipsing binaries and Cepheids. VI. Variables in the central part of M331

The DIRECT project aims to determine direct distances to two important gala xies in the cosmological distance ladder-M31 and M33-using detached eclipsi ng binaries (DEBs) and Cepheids. We present the results of the first large- scale CCD-based search for variables in M33. We have observed two fields lo cated in the central region of M33 for a total of 95 nights on the F. L. Wh ipple Observatory 1.2 m telescope and 36 nights on the Michigan-Dartmouth-M IT 1.3 m telescope. We have found a total of 544 variables, including 251 C epheids and 47 eclipsing binaries. The catalog of variables is available on -line, long with finding charts and BVI light curve data (consisting of 8.2 x 10(4) individual measurements). The complete set of CCD frames is availa ble upon request.