为了提高大口径望远镜的装调效率，对具有三点支撑变形的大口径三反射消像散望远镜在装调过程中的像散场分布进行了研究。采用矢量像差理论和孔径坐标变换，分析了在孔径光阑和非孔径光阑处反射镜存在三点支撑变形时，像散在望远镜失调和非失调情况下的分布特性。最后，在光学设计软件CODE V中利用条纹Zernike多项式Z10和Z11来模拟反射镜三点支撑变形引入的面形误差，通过实际光线追迹对像散场分布特性进行了验证。分析结果表明：当三点支撑变形位于主镜(孔径光阑)上时，不会影响望远镜的像散场分布；当三点支撑变形位于次镜或三镜(非孔径光阑)上时，将会产生与视场共轭成线性的像散项，导致望远镜在失调或非失调情况下的像散出现不同的分布特性。在最终装调时，通过分析像散场的分布可对望远镜的装调状态进行定性的分析，从而为大口径三反射消像散望远镜的装配提供指导。

In order to improve the efficiency of alignment for a three-mirror-anastigmatic (TMA) telescope with large aperture, the influence of three point mount induced (TPMI) deformation on its astigmatic field distribution in the aligning process is analyzed. Based on the vector aberration theory and aperture coordinate transformation, the astigmatic field distribution characters for the aligned and misaligned TMA telescope are analyzed with TPMI deformation on mirrors located at or away from the aperture stop. Finally, the surface error due to TPMI deformation is simulated by the optical design software CODE V using Z10 and Z11, the terms of fringe Zernike polynomial. The characteristic field distribution of astigmatism is verified by the real-ray-tracing method. The results indicate that the astigmatic field distributions are not affected when the TPMI deformation is on the primary mirror (aperture stop), and it shows different characteristic field distributions when the TPMI deformation is on the secondary or tertiary mirror (not aperture stop) for the aligned or misaligned telescope because of producing astigmatism with the field conjugated and field linear. The aligning state of TMA telescope can be qualitatively analyzed by its astigmatic field distribution at the final aligning stage, which is quite instructive for the alignment of TMA telescopes with large aperture.