An imaging system includes a spherical window, a reflector, an image sensor, a housing and a snap ring. The reflector has a focus point located at a center of a sphere defined by an outer surface of the window. Light entering the window at an angle perpendicular to the outer surface of the window and traveling to the focus point is reflected onto the image sensor by the reflector. The window and housing have first and second grooves, respectively. In order to couple the window to the housing, the snap ring is placed in the second groove, the snap ring is compressed with the window and then the snap ring is allowed to expand so that the snap ring is located in both the first and second grooves.