中国科学院南京天文光学技术研究所机构知识库

Time-domain astronomy is a cutting-edge field of research in contemporary astronomy.To survey the broadest possible range within the shortest time frame,it places specific demands on the field of view(FoV)of tele scopes.This necessitates that the optical systems of telescopes not only prioritize aperture size but also focus on the image quality across the entire FoV,aiming to achieve wide-field imaging while minimizing the impact of opti cal aberrations on astronomical research.Moreover,the wide-field telescope is more sensitive to the disturbances of optical elements,and active alignment is an indispensable key technology for ensuring and maintaining the optimal operational state of the telescope’s optical system.This paper categorizes the optical systems of wide-field telescopes into four types:prime-focus,catadioptric,Schmidt(modi-Schmidt),and three-mirror system.We analyze and in troduce the design and imaging characteristics of each optical system based on the telescopes we have developed. Additionally,we present active alignment techniques currently under development,which mainly include calculating the disturbances of optical elements through measuring the distribution ellipticity distribution of PSF over the FoVs and multi-fields wavefront detection.The analysis results indicate that the Schmidt-type structure provides a more uniform distribution of spot shapes across the entire Fo V outperforming the other three types by over four times in a 1-meter aperture.Moreover,active alignment using structured light can be implemented conveniently and can achieve nanometer-level wavefront reconstruction,which is also another relatively good option for guiding telescope alignment with high performance.