Abstract: A light intensity filter for a telescope or other optical instrument viewed by the human eye is formed of an opaque material having a plurality of holes or windows. These windows transmit a reduced amount of light to the image-forming optical component. The area of the windows relative to the area of the optical component is selected to the light intensity being imaged. The filter is especially useful for telescopes and the like, wherein the image is viewed by a human observer and the light source is momentarily of great intensity. Under these conditions the filter prevents temporary blindness of the observer due to excessive illumination, for example, tracking a moving object across the sun.