Doug Welch (The MACHO Project: Gravitational Microlensing and Millions and Millions of Stars!), is a professor in the Department of Physics and Astronomy at McMaster University in Hamilton, Ontario. His particular areas of interest are the calibration of the extragalatic distance scale using Cepheid variables. Doug developed his interest in variable stars as a teenage member of the AAVSO and continues to be involved with amateur astronomy activities as a member of the Hamilton Amateur Astronomers.

A brand new field of observational astronomy has opened up in the last few years - the study of microlensing of background sources by massive objects in the foreground. The most successful of the microlensing surveys, the MACHO Project, was formed to investigate how much of the Galaxy's so-called "missing mass" is in the form of massive, but non-luminous, objects. Doug is a member of this Science Team. In his talk, he will describe the project, its goals and its many exciting results to date. In particular, he will cover the impact of such surveys on our understanding of the distance scale through the extensive time-series of Magellanic Cloud variable stars.

More extensive information on Doug's research interests can be found on the Web at http://www.physics.mcmaster.ca/Faculty/DLWelch.html.