Product Overview: M12A7 Series Panoramic Telescopes
NSN: Various

(pictures are of M12A7)

M12A7 Panoramic Telescopes
The panoramic telescope M12A7 series is a sighting device used in conjunction with numerous field artillery pieces and various armored vehicles. It is normally used for laying the weapon in azimuth for indirect fire. However, should an emergency arise the panoramic telescope can be put into service for direct fire operation.

The characteristic feature of the panoramic telescope is that it raises the line of sight and maintains an upright image regardless of whether the line of sight is directed forward, to the side, or to the rear of the observer. The rotating head of the instrument and subsequently the line of sight may be rotated 6,400 mils in the horizontal plane by rotating the azimuth worm knob or by pushing the azimuth worm throwout lever and turning the rotating head by hand. The line of sight of the telescope can also be elevated or depressed 300 mils from the zero setting by rotating the elevation worm knob. All this can be accomplished without requiring the observer to change his position. The panoramic telescope M12A7 series are further identified by their adjustable azimuth scale assembly, collar assembly, and azimuth micrometer index. These provide a convenient means whereby slipping azimuth and micrometer scales may be adjusted, while maintaining a means for returning the scales to their original collimated setting.

The optical system is typical for the entire M12A7 series of panoramic telescopes. The image enters the telescope and the 90º prism in its correct upright position. As it is reflected from the silvered back of the prism, it leaves the prism in an inverted position. The image then enters the dove prism where it is inverted once more as it is reflected from the back of the prism. As it enters the objective lens the image is once more in its normal upright position. The objective lens focuses or converges the light rays to a point and when this lens is properly positioned, it will cause this focal point to fall exactly on the etched side of the reticle. Because the image would then appear inverted and reversed due to the crossing of the light rays at the focal point, the amici prism is positioned between the reticle and objective lens. In this position it serves two purposes: it changes the direction of the light rays 90º so they will leave through the telescope eyepiece and it inverts and reverses the image before it appears on the reticle so that when it is reversed and inverted a second time at the focal point it will then appear in its correct upright position. The image appearing on the reticle, however would be too small to serve any practical purpose. The eye and field lens correct this by magnifying the image and brightening it to make all details stand out sharply throughout the entire field.

All the panoramic telescopes of the M12A7 series are identical with the exception of the reticle used and the positioning of the rotating head with respect to the telescopes collimating tang.