PVS-4 \(see 6.1\), which is referred to herein as the objective lens.

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MIL-PRF-49366C(CR)

3.5.9.1 Adjustment accuracy. Each click of either adjustment control

shall displace the reticle pattern 0.25 � 0.04 milliradian.

3.5.9.2 Reticle excursion. The reticle adjustment controls shall move

the reticle a minimum of 2.5� in any direction from the optical axis.

3.5.9.3 Torque. The dynamic torque required to adjust the reticle

position shall be between 0.5 and 4.0 inch pounds.

3.5.9.4 Rotational alignment. The reticle shall not appear rotated

more than 1� from its proper orientation.

3.6

Environmental.

NOTE: Post-environmental verification of performance shall be Flange

focal distance (3.5.2), Veiling glare/stray light (3.5.4) and Modulation

transfer function (3.5.8). Failure to meet these requirements shall

constitute failure due to degradation of performance of input or output

characteristics per the damage technical interpretation of 3.10.1.

3.6.1 Temperature extremes. The objective shall not be damaged (see

3.10.1) by storage in any temperature from -51� to +68�C. The objective shall

not be damaged (see 3.10.1) after being subjected to repetitive temperature

changes between +23� and +68�C in a 5 minute period and between +23� and -51�C

in a 5 minute period. Soak time at temperature extremes shall be sufficient

for the entire objective to attain stabilization. Time for temperature

stabilization is defined as the amount of time required for the most internal

part of the unit under test to achieve the specified temperature.

3.6.2 Vibration. The objective shall not be damaged (see 3.10.1) after

being subjected to simple harmonic motion having an amplitude of 0.015 inch,

(0.030 inch total excursion) with the frequency being varied between 5 and 55

hertz (Hz). Vibration shall be applied in 3 mutually perpendicular planes,

one of which is perpendicular to the optical axis. The duration shall be five

(5) minutes minimum in each plane.

3.6.3 Altitude. The objective shall not be damaged (see 3.10.1) when

stored in a non-operational mode at a pressure effective to 10,000 feet

altitude above sea level for a period of not less than 3 hours.

3.6.4 Humidity. The objective shall not be damaged (see 3.10.1) when

subjected to an atmosphere with relative humidity of 95, � 5 percent over a

temperature range of +20�C to +65�C.

3.6.5 Immersion. The objective shall not be damaged (see 3.10.1) after

being immersed in fresh water to a depth of not less than 3 feet for a period

of not less than 30 minutes. The objective shall be pre-conditioned by

exposure to a temperature of +45�C �3�C for a period of 2 hours prior to being

immersed in the fresh water at a temperature of +18�C �5�C.