ABSTRACT
In this chapter, we focus on the fundamental methods of observational cosmology and summarize some of the recent observational results which have deepened our understanding of the structure and evolution of the universe. The chapter is divided into three parts. In the first section, we briefly describe the Friedmann world models, which constitute the theoretical framework, we define the main observables and we illustrate some common applications. In the second section, we describe how galaxy surveys (primarily in the optical band) are utilized to map the structure and evolution of the universe over a large fraction of its age, focusing on observational methodologies and some recent results. In the third section, we describe how surveys of galaxy clusters can be used to constrain cosmological models, and measure the fundamental cosmological parameters. Throughout the chapter, we touch only on a few recent highlights in observational cosmology. We refer the reader to fundamental textbooks, such as Longair (1998), Peebles (1993) and Peacock (1999), for a complete overview of the theoretical and observational framework.
