3.6 Extreme storage temperatures. There shall be no evidence of physical
failure such as glass breakage and bonding or casting failure due to storage
to temperatures ranging from -80° to +160°F.
3.7 Extreme operating temperature. The periscope shall meet the applic-
able requirements of 3.12.1 and 3.12.2 while exposed to and thermally stabi-
lized at -650 and +1500F.
This requirement shall be met with:
a. The periscope assembled to its mount assembly.
b. The image tube, and the reticle projector lamp energized using
6.5 +.25 volts dc.
c. A line of sight established prior to vibration.
d. The clear filter positioned in the optical train.
The periscope shall be vibrated successively along three (3) mutually perpen-
dicular axes. Vibration shall be a simple harmonic motion, the frequency
varying either linearly or logarithmically from 5 to 55 to 5 CPS in five
minute cycles for a total of 15 minutes along each of the axes. The amplitude
of vibration shall be maintained constant at 1/64 inch (1/32 inch total excur-
sion). The vibration test shall not cause:
e. Failure or flicker of light emission from the reticle projector
lamp, and image tube during vibration.
f. Evidence of physical failure during and subsequent to vibration.
g. The established line of sight to deviate more than 0.30 mil
subsequent to vibration.
3.9 Dielectric strength. This requirement shall be met with the image
tube and reticle projector lamp removed from their receptacles. Insula-
tion resistance between grounded circuits, isolated circuits, and castings
shall be not less than 10 megohms at a potential of 100 Vdc.
3.10 Optical characteristics, with imature removed. Unless otherwise
specified the requirments 3.10.1 through 3.10.6 inclusive shall be met with:
a. The image tube removed from the periscope.
b. The periscope assembly to its mount assembly
c. The clear filter positioned in the optical train.
3.10.1 Contrast transfer. The contrast transfer for vertical lines and
for horizontal lines shall be not less than the values specified in 188.8.131.52
184.108.40.206 Objective system. The following values (for the axis specified)
shall be met with 2870° ± 100° Kelvin (K) radiance, modulated at the spa-
tial frequency (angular spacing) indicated, incident to the entrance window
and the contrast values obtained at the objective system focal plane. On axis
is defined as the geometric axis of Sleeve Assy 10542215.