Scope and summary

The scope of this dissertation is twofold:

1. A description of the effect of local atmospheric turbulence on the observation performance of astronomical optical telescopes. This description includes a number of new developments and experimental results which allow to get a global view and interpretation of these phenomena.

2. A contribution to the development of engineering criteria and guidelines, which draw the practical conclusions from the research results and which should assist the civil engineer assigned to the design of a telescope enclosure.

Chapter describes the main requirements of telescope enclosures and outlines the concurrent engineering approach required to achieve an optimal design. Through the description of history cases of telescope projects, we introduce the main issues and open questions related to local atmospheric turbulence and their consequences on the telescopes' performance and on the engineering of telescope enclosures. The last section of the chapter (§, page ) summarizes these issues which constitute the main research object of the dissertation and are then expanded in the next chapters.

Chapter describes the aerodynamic environment surrounding a telescope. Two distinct aspects are studied by means of wind tunnel and full scale experiments: the first one concerns the characterization of the wind turbulence on the upper part of the telescope, which is responsible for high frequency guiding errors. The second aspect analyzes the turbulent pressure fluctuations on the primary mirror and their relationship with optical aberrations.

In chapter we analyze the local seeing effects, caused by refractive inhomogeneities of the atmosphere caused by the telescope and by the observatory itself. The different contributions from the primary mirror of the telescope, the enclosure and the atmospheric surface layer are elucidated by means of experimental measurements, theoretical analysis and numerical simulations.

Chapter introduces a system engineering approach in which the different contributions to the telescope image quality can be combined for a global evaluation of performance of the telescope and the influence of the enclosure.