Modern astronomical observatories are becoming larger and more complex with many components working together to achieve the common goal of gathering useful information for astro-scientists. Successful engineering of these observatories is enabled by following a systems engineering viewpoint of looking at the whole. This viewpoint requires a multidisciplinary breadth and the ability to find a balance among 1) the system user's needs and desires, 2) the manager's funding and schedule constraints, and 3) the capabilities and ambitions of the engineering specialists who develop and build the system. The system engineer is sometimes described as the person on the program who should know the partial derivative of every parameter of the system with respect to every other parameter. This course introduces the concepts and models that are used to evolve a system from an abstract vision to the final validated and verified operational system. Examples are given that provide insight into the variety of engineering disciplines and typical subsystems found in observatories for optical astronomy observatories (X-ray through IR).