18.104.22.168 Vibration "B".- The sight's projected reticle image shall
not be displaced more than + 5 mils during this vibration from its initial
position prior to vibration. This vibration shall be in a vertical plane
for 5 minutes q 15 seconds at a frequency of 32 cps with an amplitude of
0.015 inch (0.03 inch total excursion).
3.7.2 Optical-mechanical alignment.
22.214.171.124 Azimuth alignment.- The line of sight through the geometric
axis of the projected reticle pattern shall be adjustable and capable of
being-locked-at any angle between 2.5° right and 0.5° left of a plane
that is parallel to the vertical plane through reference line X (See
126.96.36.199 Elevation alignment.- The line of sight through the geometric
axis of the--projected reticle pattern shall be parallel to reference line W
(Figure 1) within 4.O mils with Arm 10547473 in the operating position and
Bell Crank 10547317 mobilized.
3.7.3 Optical-mechanical alignment retention.- The optical-mechanical
alignment demonstrated by the sight in 3.7.2 shall not change more than
+ 0.5 mil when Arm 10547473 is repeatedly moved from its operating to stowed
to operating position, or when the sight is repeatedly elevated 177 roils
and depressed 408 roils or removed and reinserted into its orientation
3.7.4 Extraneous light emission.- The light source shall not be
visible except as observed through the lenses.
3.7.5 Projected reticle image definition.- The projected reticle
image shall be clearly defined with no visible breaks when viewed from a
normal operating position against a bright background (such as the reflec-
tion of a clear sky from water) or when viewed in a darkened area.
3.7.6 Projected reticle image pattern accuracy.- The angle subtended
by the inner circle of the projected reticle image pattern shall be
30 + l.0 mil.
3.7.7 Parallax.- When viewing at a distance of eight to ten inches
from the beamsplitter, -parallax between the reticle image center and the
target shall not exceed 2.0 roils over the full aperture of the beamsplitter
when viewing a target at a range of 1000 + 200 meters.
3.7.8 Image tilt." The vertical line of the projected reticle image
shall be plumb within 1.0 degree when meeting 3.7.2.
3.7.9 Elevation accuracy.- With the elevation position established in
188.8.131.52, the angular changes in the line of sight between 214 roils depression
and 177 mils elevation shall be within 2.0 mils of the same angular changes
in Refernce Line "w". The angular changes in the line of sight, between
214 mils depression and 408 roils depression shall be within 4.0 roils of the
same angular change in Reference Line W".