During operation, astronomical telescope will undergo thermal disturbance, especially more serious in solar telescope,
which may cause degradation of image quality. As drives careful thermal load investigation and measure applied to
assess its effect on final image quality during design phase. Integrated modeling analysis is boosting the process to find
comprehensive optimum design scheme by software simulation. In this paper, we focus on the Finite Element Analysis
(FEA) software-ANSYS-for thermal disturbance analysis and the optical design software-ZEMAX-for optical system
design. The integrated model based on ANSYS and ZEMAX is briefed in the first from an overview of point.
Afterwards, we discuss the establishment of thermal model. Complete power series polynomial with spatial coordinates
is introduced to present temperature field analytically. We also borrow linear interpolation technique derived from shape
function in finite element theory to interface the thermal model and structural model and further to apply the
temperatures onto structural model nodes. Thereby, the thermal loads are transferred with as high fidelity as possible.
Data interface and communication between the two softwares are discussed mainly on mirror surfaces and hence on the
optical figure representation and transformation. We compare and comment the two different methods, Zernike
polynomials and power series expansion, for representing and transforming deformed optical surface to ZEMAX.
Additionally, these methods applied to surface with non-circular aperture are discussed. At the end, an optical telescope
with parabolic primary mirror of 900 mm in diameter is analyzed to illustrate the above discussion. Finite Element
Model with most interested parts of the telescope is generated in ANSYS with necessary structural simplification and
equivalence. Thermal analysis is performed and the resulted positions and figures of the optics are to be retrieved and
transferred to ZEMAX, and thus final image quality is evaluated with thermal disturbance.