Thermal characteristics of a classical solar telescope primary mirror

TL;DR

This study models the thermal and structural behavior of a 2m solar telescope mirror made of Silicon Carbide and Zerodur, considering daily heat load variations to inform effective thermal control strategies.

Contribution

It provides a detailed 3D heat transfer analysis comparing Silicon Carbide and Zerodur for solar telescope mirrors under realistic environmental conditions.

Findings

Silicon Carbide shows superior heat conductivity, reducing thermal gradients.

Zerodur maintains minimal thermal expansion, ensuring optical stability.

Simulations suggest optimal thermal management strategies for each material.

Abstract

We present a detailed thermal and structural analysis of a 2m class solar telescope mirror which is subjected to a varying heat load at an observatory site. A 3-dimensional heat transfer model of the mirror takes into account the heating caused by a smooth and gradual increase of the solar flux during the day-time observations and cooling resulting from the exponentially decaying ambient temperature at night. The thermal and structural response of two competing materials for optical telescopes, namely Silicon Carbide -best known for excellent heat conductivity and Zerodur -preferred for its extremely low coefficient of thermal expansion, is investigated in detail. The insight gained from these simulations will provide a valuable input for devising an efficient and stable thermal control system for the primary mirror.