"It is forbidden to turn on during the day without a diaphragm and direct into a bright light." This inscription is made on the device, which was one of the first devices, as they would say now, night vision - for military small arms. We are talking about a device designated as NSP (NSP-2) - a night rifle scope.
For the first time, the NSP device was used on an automatic weapon, namely, on a Kalashnikov assault rifle in the 1950s. Speaking specifically about the NSP-2, it began to be installed in 1956 on the 7.62 mm Kalashnikov assault rifle of the AKMSN modification.
The night rifle scope made it possible to conduct aimed shooting at targets in the dark, which, for obvious reasons, increased the effectiveness of the use of firearms. However, this complex certainly cannot be called easy to use. There are reasons for this.
To begin with, it is worth noting that the NSP (NSP-2) was used not only on Kalashnikov assault rifles. They were also equipped with RPD (Degtyarev light machine guns), as well as hand-held anti-tank grenade launchers (RPG-2).
The principle of operation of the night rifle scope belongs to the principles typical for illuminated scopes. The target was illuminated by a powerful headlamp. For obvious reasons, the principle is not at all the same as is characteristic of night vision devices today.
The photographs show that the NSP (NSP-2) is a device of impressive dimensions. It was connected to an assault rifle, machine gun or grenade launcher using a special dovetail mount. At the same time, the night rifle scope itself weighed almost 5 kg (4.9 kg in the firing position). For its operation, a rechargeable battery was required, the mass of which was about 2 kg. The total mass of the complex based on the AKMSN with all the aiming devices was 16 kg, unthinkable today. At the same time, firing using such an aiming system was limited to about 3.5 hours - after that it was necessary to change the battery.
Indicators of the field of view for NSP-2 - 8 degrees. In this case, the scattering angle of the searchlight, which was part of the complex, is up to 6 degrees.
The complete list of items included in the NSP-2 of the 1950 model is impressive in its vastness: in addition to the scope with the diaphragm itself, it is a power supply with a low-voltage converter and a 3SC-25 battery, a bag, a case, numerous spare parts and accessories, including a light filter, a frame, drying cartridge, RB-3 spark gap, spare battery, protector, two headlights, contact nuts to the battery.
On the sighting complex there was a special regulator, which made it possible to adjust the modes of its operation depending on the approximate range of the target, where 1 - 100 m, 2 - 200 m, 3 - 300 m, 5, 7, 9 - 400, 500 and 600 m, respectively … Moreover, such modes were used for the Kalashnikov assault rifle and RPD.
To prevent the power cord from interfering with the shooter as much as possible, it was attached to the body with a special bracket.
Such equipment for conducting aimed shooting at night was supplied, among other things, for the Airborne Forces of the USSR.
It is not hard to imagine how much effort it took to at least set up this entire sighting system for firing, not to mention how much effort was expended in carrying it as part of a soldier's general equipment.