一、概述中性滤光镜对对空望远系统来说,是必不可少的一种减光元件。由于以天空为背景的目标,其亮度变化较地面目标亮度变化大得多,加上背景亮度差别也很大,故在光学系统中设置活动中性滤光镜,可以协调视场内目标的亮 First, an overview of the neutral filter on the telescope system, it is essential to a light-reducing components. Due to the sky as the background of the target, the change in brightness than the ground target brightness is much greater changes, coupled with the background brightness is also very different, so set the active neutral filter in the optical system, you can coordinate the field of vision within the target bright