The resolution capabilities of computer image generators (CIG) used for simulation and training have advanced to the degree that they exceed the capabilities of existing shadow mask, direct view color TV displays and color TV projectors. One solution to this problem is the modern day implementation of a trinoscope color display that uses the optical merging of three high resolution monochrome cathode ray tubes-red, green, blue color phosphors, respectively-to produce a full color image. Such systems are particularly suitable for telescopes and periscopes needed in tank or submarine simulations where the color-combining optics can be integrated into the simulated sight optics. This paper describes the technical advances required to assure maximum resolution and, more importantly, superior color convergence (i.e., the capability to make the three CRT images fall exactly on top of each other so that the resulting full color image is produced without undesirable color fringing).