南极红外巡天望远镜红外背景辐射抑制方法

Infrared Background Radiation Removing Design and Simulation of Antarctic Survey Telescope

南极Dome A被认为是地球上最为优秀的天文测光、观测台址,尤其在红外波段。为了充分利用Dome A的独特天文观测优势条件以及满足系外行星观测需求和为我国未来南极更大口径望远镜的研制提供经验,提出建造1m可见/红外巡天望远镜。通过掩星法探测系外行星,至少需要万分之五的测光精度,必须很好地抑制或降低系统光机结构的自身辐射。以南极1m可见/红外巡天望远镜为例,进行南极红外望远镜杂散光抑制方法方面的探讨。由于该望远镜采用一次直接成像光学系统,光学结构简单,但无法设置冷光阑,红外背景辐射抑制效率较低。在光学系统设计上把次镜设置为孔径光阑进行优化设计,再详细介绍主镜遮光罩,次镜遮光罩,以及杜瓦瓶内冷光栏的独特设计,通过模拟仿真,自身辐射在像面上的辐照度为6.8×10-10 W/m2,为天空背景辐射在像面上的照度五分之一以下,满足天文观测三分之一要求。

Antarctic Dome A is considered to be the most outstanding astronomical photometry and observation site on earth, particularly in the infrared. To take full advantage of the unique advantages for astronomical observation, meet the needs of exoplanet observations and provide experience for the future development of larger antarctic telescopes, the construction of 1 m visible/infrared survey telescope is proposed. By occultation method to detect exoplanets, it should achieve five ten thousandths of photometric accuracy by reducing background radiation, suppressing the self-radiation of telescope is very important. Take 1 m visible/infrared sky survey telescope as an example, the method of suppression of self-radiation is discussed. One meter antarctic visible/infrared survey telescope adopt a direct, simple optical system, but can not be set the cold pupil, suppressing stray light is less efficient. By optimizing the design of the optical system, setting the secondary mirror as aperture, the unique design of the Dewar, secondary baffle and main baffles, the background radiation on imaging surface is 6.8 × 10 ^-10 W/m2 Through simulation, which is one-fifth of the sky background radiation, the background radiation suppression meets the requirements of astronomical observations.