Practices of Celestial Observation in the Islamicate World1

Abstract

This chapter surveys two types of social practices as they pertained to observations. First, short- or long-term observations were undertaken by individual scholars or within a family or workshop context. Second, observations were carried out by larger groups of scholars, craftsmen and administrators within the context of a long-term program, often including the construction of an observatory with specialized buildings and fixed instruments with large scales. Long-term group activities were enabled by substantive patronage, normally by a ruler but occasionally also by a vizier or an affiliated prince. Many of the individual observation projects and all group projects led to the compilation of a set of astronomical and astrological tables called a zīj (pl. zijes). But individual projects also occurred on a more limited scale of purpose and duration. Examining currently published research results yielded the remarkable insight that many more long-term observation projects have taken place than previously thought, often as individual efforts.