Direct Distances to Nearby Galaxies Using Detached Eclipsing Binaries and Cepheids. Ii. Variables in the Field M31a Based on the Observations Collected at the Michigan-dartmouth-mit (mdm) 1.3-meter Telescope and at the F. L. Whipple Observatory (flwo) 1.2-meter Telescope

We undertook a long term project, DIRECT, to obtain the direct distances to two important galaxies in the cosmological distance ladder – M31 and M33, using detached eclipsing binaries (DEBs) and Cepheids. While rare and difficult to detect, detached eclipsing binaries provide us with the potential to determine these distances with an accuracy better than 5%. The massive photometry obtained in order to detect DEBs provides us with the light curves for the Cepheid variables. These are essential to the parallel project to derive direct Baade-Wesselink distances to Cepheids in M31 and M33. For both Cepheids and eclipsing binaries the distance estimates will be free of any intermediate steps. As a first step of the DIRECT project, between September 1996 and January 1997 we have obtained 36 full nights on the Michigan-Dartmouth-MIT (MDM) 1.3-meter Based on the observations collected at the Michigan-Dartmouth-MIT (MDM) 1.3-meter telescope and at the F. L. Whipple Observatory (FLWO) 1.2-meter telescope On leave from N. Copernicus Astronomical Center, Bartycka 18, Warszawa 00–716, Poland