Yamazaki Atsushi, Yamada Manabu, Lee Yeon Joo, Watanabe Shigeto, Horinouchi Takeshi, Murakami Shin-Ya, Kouyama Toru, Ogohara Kazunori, Imamura Takeshi, Sato Takao M, Yamamoto Yukio, Fukuhara Tetsuya, Ando Hiroki, Sugiyama Ko-Ichiro, Takagi Seiko, Kashimura Hiroki, Ohtsuki Shoko, Hirata Naru, Hashimoto George L, Suzuki Makoto, Hirose Chikako, Ueno Munetaka, Satoh Takehiko, Abe Takumi, Ishii Nobuaki, Nakamura Masato
1Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 Japan.
2Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan.
Earth Planets Space. 2018;70(1):23. doi: 10.1186/s40623-017-0772-6. Epub 2018 Feb 12.
The ultraviolet imager (UVI) has been developed for the spacecraft (Venus Climate Orbiter mission). The UVI takes ultraviolet (UV) images of the solar radiation reflected by the Venusian clouds with narrow bandpass filters centered at the 283 and 365 nm wavelengths. There are absorption bands of SO and unknown absorbers in these wavelength regions. The UV images provide the spatial distribution of SO and the unknown absorber around cloud top altitudes. The images also allow us to understand the cloud top morphologies and haze properties. Nominal sequential images with 2-h intervals are used to understand the dynamics of the Venusian atmosphere by estimating the wind vectors at the cloud top altitude, as well as the mass transportation of UV absorbers. The UVI is equipped with off-axial catadioptric optics, two bandpass filters, a diffuser installed in a filter wheel moving with a step motor, and a high sensitivity charge-coupled device with UV coating. The UVI images have spatial resolutions ranging from 200 m to 86 km at sub-spacecraft points. The UVI has been kept in good condition during the extended interplanetary cruise by carefully designed operations that have maintained its temperature maintenance and avoided solar radiation damage. The images have signal-to-noise ratios of over 100 after onboard desmear processing.
紫外成像仪（UVI）是为航天器（金星气候轨道器任务）研制的。UVI利用以283纳米和365纳米波长为中心的窄带通滤光片拍摄金星云层反射的太阳辐射的紫外图像。在这些波长区域存在SO和未知吸收体的吸收带。紫外图像提供了云顶高度附近SO和未知吸收体的空间分布。这些图像还使我们能够了解云顶形态和霾的特性。以2小时为间隔的名义序列图像用于通过估计云顶高度处的风矢量以及紫外吸收体的质量输送来了解金星大气的动力学。UVI配备了离轴折反射光学系统、两个带通滤光片、一个安装在由步进电机驱动的滤光轮中的漫射器以及一个带有紫外涂层的高灵敏度电荷耦合器件。UVI图像在星下点的空间分辨率范围为200米至86千米。通过精心设计的操作，在延长的行星际巡航期间，UVI一直保持良好状态，这些操作维持了其温度并避免了太阳辐射损伤。经过机载去拖影处理后，图像的信噪比超过100。
