Abstract: A surveying target having a housing with one open side, encloses a high intensity gas discharge flash tube. A light absorbing surface in the housing bounding the back and sides of said flash tube prevents reflection of light, thereby maintaining a relatively discrete outline. A light transparent cover member on said open side for passing light from said high intensity gas discharge tube toward an observer. A transmitter and receiver, and including resettable code devices are provided for limiting responsive operation only to transmitters transmitting a preassigned code and a corresponding receiver for detecting said preassigned code. A light transparent cover member filters light from said lamp of a predetermined wave length. A surveying system using an optical instrument for binocular visioned observers is also disclosed.