Abstract: A collimator is compact and uses power efficient light emitting diodes as the illumination source to generate a test image in collimated space. The collimator provides a test image across a wide field of view, which is useful for calibration of optical devices that have a wide field of regard. An optical projection system in the collimator utilizes an array of light emitting diodes, whose light is converged by a Fresnel lens, through a holographic diffuser plate, onto a target plate bearing the test pattern to be projected out into collimated space through a converging lens. An alignment structure provides translation of the target plate along the main axis of the collimator and provides rotational freedom about two axes (vertical and horizontal) via a gimbal structure mounted on the translation mechanism.