obscuration
n. 遮蔽，昏暗；晦涩；掩星
例句
Deal with the causes of obscuration, not with the sun.
（比如眼翳）需要治理的是障碍的成因，而非太阳。
Fire hazard testing - part 6-2: smoke obscuration; summary and relevance of test methods.
火灾试验。第6 - 2部分：烟雾不透明度。试验方法的概要及其相关方面。
In order to reduce the obscuration, conical baffle of secondary mirror is ameliorated into a shutter one.
为了减小初始中心遮光比，将次镜锥状遮光罩改进为百叶窗式结构；
