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Page Title:
Reticle accuracy (collimation). |
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|  MIL-A-48449A(AR)
4. 6.8 Purging.
Upon satisfactory completion of the sealing
test, the alignment device shall be flushed with dry nitrogen
gas.
The flushing shall be accomplished by opening the purging
vent and allowing the nitrogen gas to flow through the Alignment
Device until the bled gas conforms to the dew point requirements
of 3.9.2 as measured with a dew point tester.
Close the purging
vent.
4.6.9
Cleanliness.
The Alignment Device, with Collimator
Assembly D7573433, shall be subjected to the applicable test
procedures outlined in MIL-O-1383C to determine compliance with
the requirements of 3.9.3.1 and 3.9.3.2.
4.6.10
Reticle accuracy (collimation) .
With the Alignment
Device positioned as specified in 4.6.1, observe where the
Alignment Device's boresight cross falls upon the target in the
Collimator Assembly.
The intersection of the boresight cross
shall not deviate from the collimator target zone in excess of
the limit specified in 3.9.4.1.
Remove and reposition the unit
under test three times.
At each resetting into the fixture, the
boresight cross in the alignment device shall remain centered
within the specified limits to ascertain compliance with
requirement of 3.9.4.2.
4.6.11
Parallax.
Test shall be performed using the set-up
in 4.6.1 with the 80 meter focus in the Collimator Assembly.
Parallax shall be recognized as any apparent displacement, when
the observer's head is moved from side to side or up and down.
Any movement between the collimator's reticle and the alignment
device reticle shall not exceed the value specified in 3.9.5.1.
(The width of a reticle line in the collimator is equal to 0.10
mil).
4.6.12
Reticle Illumination.
The test shall be performed
in an area in which ambient lighting can be varied.
Personnel
performing the testing are to be dark adapted by being in the
darkened room for at least 15 minutes before viewing the
reticle.
The reticle shall be viewed through the collimator
assembly using a 4-power telescope at a distance of 10 feet
1
foot.
The reticle marking shall be clearly distinguishable
with and without the use of a 50% neutral density filter while
the light level is varied gradually from O to 10 foot candles
over a period of 1 to 2 minutes.
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