Abstract: An aiming device of the general type shown in U.S. Pat. No. 2,488,541 is disclosed. The device comprises a tubular housing for mounting on a gun or other device which must be manually aimed and the housing contains a spot source of light which is projected rearwardly toward one eye of the user through a collimator contained within the housing. The light source is preferably a radiation activated phosphor of one color housed in a filter of a different color in order to present automatically a spot source of light of the color of the filter during high ambient lighting intensity and a spot source of light the color of the phosphor during low ambient lighting intensity.