A sight assembly for mounting to a weapon. A holographic optical element and a light source are in a fixed angular configuration with respect to one another, but may be adjusted either together or individually in a horizontal or vertical direction. The sight assembly may have a mirror or lens. An adjustment mechanism is provided where a shaft includes at least two portions wherein the two portions of the shaft of the screw have different pitch directions and/or pitch dimensions allowing for slight adjustment the assembly. The light source may be a vertical-cavity surface emitting laser (VCSEL). A temperature sensor may sense a temperature of the VCSEL. A current to the VCSEL may be adjusted based on a change in the temperature such that the output wavelength is approximately the same as a desired wavelength. The assembly may further allow for perceived image distance adjustment using parallax mismatch.