*ALWAYS REMEMBER : No matter how bright the night may appear
to be, it will never allow the human eye to function with daylight precision.
For maximum effectiveness, the sniper must apply the following principles of
night vision.*
- Darkness Adaptation: It takes the human eye about thirty minutes to adjust
itself to a marked lowering of illumination During that time the pupils
are expanding and the eyes are not reliable. In cases where the sniper
team is to depart on a mission during darkness, it is recommended that
they wear sunglasses or red-lens goggles in lighted areas prior to their
departure.
- Off Center Vision: Off center vision is the best method of
observing at night. It is the technique of focusing attention on an object
without looking directly at it. An object under direct gaze in dim light
will blur and appear to change, sometimes fading out completely. If the
eyes are focused at different points around the object, about five to ten
degrees away from it, your peripheral vision will provide a true picture
of it. The reason for this is the portion of the eye that functions in
reduced light is located around the outside edge of the retina.
- Factors Effecting Night Vision: Of the factors effecting
night vision the sniper has control over the following:
- Lack of vitamin A impairs night vision. However., an overdose of will
not increase your night vision capability.
- Colds, fatigue, narcotics, headaches, smoking and alcohol will reduce
night vision.
- Exposure to bright light impairs night vision and necessitates a re
adaptation to darkness.
- Darkness blots out detail and color so a sniper must compensate by
learning to recognize objects by and bodies by outline alone.
During the twilight hours the constantly changing natural light levels cause
rapid shadow movement that the sniper must be aware of. This constant change
in the light level also causes an equally constant process of eye adjustment.
- Twilight: Twilight induces a false sense of security, and
the sniper must be extremely cautious. For the same reason the enemy is
prone to carelessness and will be more likely to expose himself. This is the
time when most LPs and OP's will be moving about This is a good time to note
their locations for future reference. The cross hairs on the Unertl scope
are visible and accurate from about one half hour before sunrise and one
half hour after sunset. Begin morning nautical twilight (BMNT) and end
evening nautical twilight (EENT) will vary from season to season. Other reticules
like the German #1 are more effective during twilight and can extend those
shooting hours a little.
- Illumination Aids: On occasion, the sniper may have the
assistance of artificial illumination for observation and shooting.
Examples are:
- Cartridge, Illuminating, M301A2 - 50,000 candlepower.
- Zenon searchlights mounted on tanks - 50,000,000 candlepower.
- Campfires, street lights and buildings often provide enough light to see
and reduce a target.
Binos as an observation aid.
- Binoculars: Of observation aids, the binoculars are the
easiest to use. They are easily manipulated and the field of view is limited
only by the snipers scanning ability. Each sniper team will be equipped with
binos to aid in searching for and selecting targets. The binocular, 7x50
(Standard military issue),
has seven power magnification and a 50mm objective lens. Focusing adjustments
are on the eyepieces with separate adjustments for each eye. One monocle has
a horizontal and vertical scale, graduated in mils, that is visible when the
binos are in use.
- Method of Holding Binoculars:
- Binos are held lightly, monocles resting on the and supported by the
heels of the hands.
- The thumbs are used to block out light that would enter between the
eyes and the eyepiece.
- The eyepieces are held lightly to the eyes to avoid transmission of
body movement.
- Whenever possible a stationary rest should be used to support the
elbows and/or the binos. Having the best pair of binos in the world
will do you no good if they are not adjusted correctly. There are two
adjustments needed, the interpupillary and the focal.
- interpupillary Adjustment: The interpupillary distance
(distance between the eyes ) varies with individuals. The two monocle
that make up a pair of field glasses are hinged together so that the
receptive lenses can be centered over the pupils of the eyes. Most binos
have a scale on the hinge, allowing the sniper to preset the glasses for
interpupillary distance. This will reduce unnecessary eye strain. To
determine this setting, the monocles are adjusted until the field of
vision ceases to be two overlapping circles and appear as a single sharply
defined one.
- Focal Adjustment: Each individual eye of that individual
requires different focus settings. To adjust your binos follow these steps:
- With both eyes open look at a distant object.
- Close the objective lens dust cover on the right monocle and turn the
focus ring on the left eyepiece until the object is sharply defined.
- Repeat the procedure for the right monocle.
- Read the diopter scale on each focusing ring and record for future
reference.
- Binos should always be focused prior to putting them up to your eyes
to reduce unnecessary eye strain.
- Reticle: The reticle pattern found in one of the monocles
of the binoculars is a mil scale (see mil-dots section).
It is used in adjusting artillery and
estimating range. in older military binos, the reticle was etched onto
the objective lens. On the newer ones the reticle is laminated onto the
inside of the objective lens, so care must be taken not to leave these
binos unattended while exposed to direct sunlight. The reason for this is
that the sun could melt the reticle off. Palm sized binos as made by such
companies as Tasco, Nikon etc.. could be carried by the sniper to assist
him in his observations. They are smaller than the 7x50’s and are very
easy to carry. The only limiting factor is the smaller objective lens.
The smaller are usually 8x30 which is a slight handicap at night but will
not effect you during daylight. These mini bino's are easy to drop into a pocket
and are very valuable while stalking.
- M49 & M144 Spotting Scopes: The M49 scope is a prismatic optical
instrument with a 20 power magnification and is still carried
by USMC snipers but is no longer issued to US Army snipers. The US Army adopted
the M144 15-45x spotting scope. The spotting scope is carried by the sniper team
whenever justified by the mission. The lens of these scopes are coated with a
hard film of magnesium fluoride for maximum light transmission. This coating
along with high magnification makes observation and positive identification on
camouflaged targets at longer distances or in shadows possible. The process
of observation is planned and systematic. Your first consideration is
towards any immediate danger towards yourself, so you begin with a hasty
search of the entire area. This is followed by a systematic and deliberate
observation called a detailed search As long as you and your partner remain
in position, you and your partner maintain a constant surveillance by
repeating hasty and detail searches.
- Hasty Search: A hasty search is a very rapid check for enemy
activity conducted by both the sniper and the observer. The observer makes
the search with the 7x50 binos, making quick glances at specific points
throughout the area, not by viewing the terrain in one continuous panoramic
sweep. The binos are used in this type of search because they afford the
observer with a wide field of view necessary to cover a large area in a short
period of time. The hasty search is effective because the eyes are sensitive
to any slight movements occurring within the arc of the object
they are focused on. The sniper, when conducting his hasty search, uses
what is called side vision or peripheral vision. But in order for this side
vision to work, the eyes must be focused on a specific point on order to
have ibis sensitivity.
- Detailed Search: If the sniper team fails to locate the
enemy during the hasty search, they must then begin a systematic and
deliberate examination known as a detailed search. Again, the observer
uses the 7x50 binos, affording him the widest view available. The search
should begin with the terrain nearest your position, because it normally
offers the greatest danger. Your detailed search should start at a point
fifty meters to either flank. You then scan in a 180 degree arc, searching
everything in exacting detail. When you reach the opposite flank, scan back
across your front, ensuring that you slightly overlap your last scan.
Continue making overlapping strips until you reach your far limits. This
method of observation is known as the fifty meter overlapping strip method.
Only when the sniper team spots a target or a suspicious object will they
switch to the spotting scope to make a positive identification or detailed
description of the object. To use the spotting scope any more than this,
you run the risk of extreme eye fatigue. While conducting these searches
the team must make mental notes of prominent terrain features and areas
that may offer the enemy cover and concealment. These areas should also be
noted an the sketch.
- Maintaining Observation: Once again, the best instrument
for making both hasty and detailed searches are the binos. After completing
the detailed search the sniper team will maintain a constant observation of
the area. This is done by making quick glances at various points throughout
the entire area, focusing the eyes on specific points. Since it is possible
that a hasty search may fail to locate any enemy activity, the team must
periodically make detailed searches, especially if the team must alternate
duties as observer/sniper so as to reduce fatigue.
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