| Large aperture telescope play a key role in modern society. The factors which hadeffects on imaging resolution of large aperture telescope besides the manufacturingquality of primary mirror, assembly and adjustment error, deformation caused by theweight, but also thermal deformation and thermal boundary layer emerging solartelescope. A large aperture light weight primary mirror of telescope had been study andsome control measurement had been carried out aimed at the later two problemsmentioned above.The uniform temperature distribution had few effects on mirror surface. Radialtemperature difference and axial temperature difference had much more serious effectson primary mirror surface, especially the axial one. The fluctuation of ambiencetemperature would lead to serious axial temperature difference. Therefore the mirrorsurface would suffer severe effects from the temperature fluctuation. A measurementhad been proposed and simulation had been conducted. Simulation demonstrated theincrease of surface quality.The local temperature had a rapidly incremental within tens of seconds when heatedby radiation.The study proposed that the lower absorption rate and lower thermalexpansion coefficient material would result well performance when heated by radiation.The thermal boundary layer effects resulted from the hot mirror surface heated byradiation had server effects on optical wave front in the situation of natural convection.The obviously optical aberrations were Spherical aberration and result the Strl Ratiobelow0.1in most of the time. Here a scheme of air knife crossing the mirror surfacehad been proposed and simulation had been conducted. It demonstrated a perfect work.The Strl Ratio could hold on above0.69during the working time without defocusaberration.The thesis contributed the knowledge about thermal characteristic and thermalboundary layer effects of large aperture light primary mirror and provided reference forlarge aperture telescope design. |
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