1PN51-2 ( rus, 1ПН51-2) is the
GRAU index
The Main Missile and Artillery Directorate of the Ministry of Defense of the Russian Federation (), commonly referred to by its transliterated Russian acronym GRAU (), is a department of the Russian Ministry of Defense. It is subordinate to the ...
for a Soviet designed passive
night scope
A night-vision device (NVD), also known as a night optical/observation device (NOD), night-vision goggle (NVG), is an Optoelectronics, optoelectronic device that allows visualization of images in low levels of light, improving the user's night ...
for the
RPG-29
The RPG-29 "Vampir" (Russian for "vampire") is a Soviet reusable rocket-propelled grenade (RPG) launcher. Adopted by the Soviet Army in 1989, it was the last RPG to be adopted by the Soviet military before the fall of the Soviet Union in 1991.
T ...
rocket launcher. ''1PN'' is the GRAU index of night vision devices, where PN stands for ''Nochnoy Pritsel'' ( rus, Ночной прицел) meaning night sight.
The scope weighs 2.1 kg and measures 280 mm × 192 mm × 106 mm (length × height × width). It is thus more compact than the similar multi-model
1PN51 night vision scope.
It is attached onto a matching side rail on the RPG after which a lever on the scope is pressed to hold it in place.
It comes in a metal container with room for extra batteries, battery charger and the other accessories, weighing 6.45 kg in total.
Optics
The scope gathers light via an 80 mm
aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane.
An opt ...
into a reflector with the
secondary mirror
A secondary mirror (or secondary) is the second deflecting or focusing mirror element in a reflecting telescope. Light gathered by the primary mirror is directed towards a focal point typically past the location of the secondary. Secondary mirr ...
obscuring the central 42 mm of the aperture.
The top of the scope has two perpendicular knobs for zeroing the sight.
The aperture cover itself has two 12 mm apertures that can be opened partially allowing the scope to be used in light conditions that would otherwise saturate the light intensifier.
The rear end of the scope is a focus dial.
The eyepiece has a detachable soft rubber eyecup.
The scope has a magnification of 2.94.
Light Intensifier and Reticle
Below the aperture the device has a brightness knob. Apart from powering on and off the device, this knob controls the brightness of the
reticle
A reticle, or reticule also known as a graticule, is a pattern of fine lines or markings built into the eyepiece of an optical device such as a telescopic sight, spotting scope, theodolite, optical microscope or the screen of an oscilloscope, ...
allowing for the reticle to be visible without outshining the target.
The reticle has markings that match the height of a typical armoured vehicle at ranges 200 m, 300 m, 400 m and 500 m.
Power
The light intensifier is powered by a pack of 5 D-0,55S ( rus, Д-0,55С) rechargeable cells, providing up to 7 V. The scope requires 6 V ± 1 V. The maximum current drawn is 40 mA.
The D-0,55S battery pack is used by a range of devices including 1PN51 and
1PN58 and has a separate charging device. The charging device has a switch to select one of 12 V or 27 V input and two red control lamps, one to indicate that power is available and one to indicate that charging is complete.
Image gallery
File:1PN51-2 Set (1 of 5).jpg, A 1PN51-2 with bag, manual, battery packs (one disassembled), battery charger w. cable
File:1PN51-2 Zeroing (2 of 5).jpg, The two knobs for zeroing a 1PN51-2
File:1PN51-2 Brightness (3 of 5).jpg, The knob for controlling the 1PN51-2 reticle brightness
File:1PN51-2 Battery (4 of 5).jpg, Three battery packs for the 1PN51-2, two of which are disassembled
File:1PN51-2 Reticle (5 of 5).jpg, The 1PN51-2 Reticle
References
*{{cite book, title=ИЗДЕЛИЕ 1ПН51-2 ТЕХНИЧЕСКОЕ ОПИСАНИЕ И ИНСТРУКЦИЯ ПО ЭКСПЛУАТАЦИИ , trans-title= PRODUCT 1PN51-2 TECHNICAL DESCRIPTION AND OPERATING INSTRUCTIONS, date= September 1991 , no-pp=yes, pages= 52 pages, language= ru
Military electronics of Russia
Night vision devices