18.104.22.168 Spherical power.- Following was the ring and shelf life
exposure the periscope shall meet the requirement of 3.5.2 except that
spherical power shall be within the range of minus 0.60 to plus 0.30
22.214.171.124 Astigmatism and light transmission.- Following weathering
and shelf life exposure the periscope shall meet the requirements of 3.503
and 3.5.4 except that astigmatism and light transmission shall not degrade
in excess of 20 percent of the value recorded prior to was the ring and
shelf life tests.
3.4.2 Shock. - The periscope shall not be damaged after being subjected
to the test specified in Specification MIL-O-13830, after which it shall
meet all requirements of this specification.
failure and shall meet the requirementst of thiS Specification at room tem-
perature (60 to 90 degrees Fahrenheit) after being exposed to ambient tem-
peratures of plus 160 and minus 65 degrees Fahrenheit.
3.4.4 Mirror and window laminations. - Mirror and window laminations
shall not be damaged when sub jetted to the temperatures specified in 3.4.3.
The appearance of bubbles, blisters or other indications of cement separa -
tion shall be considered evidence of bond failure.
3.5 Optical characteristics.
3.5.1 Resolution. - The periscope shall permit resolution of a test
pattern subtending 1 minute of arc within the resolving area as outlined
on the applicable drawing specified in 2.1.
3.5.2 Spherical power. - Spherical power shall be within the range of
minus 0.50 to plus 0.25 diopter.
3.5.3 Astigmatism.- Astigmatism shall mot exceed 0.25 diopter.
3 .5.4 Light transmission. - Light transmission shall not be less than
3.6 Bubbles and inclusions. - Bubbles and inclusions (excepting lint)
shall not exceed 0.040 inch in maximum diameter and the total projected
area (perpendicular to the light path) of all bubbles and inclusions shall
not exceed 0.05 percent of the cross-sectional area of the plastic body
perpendicular to the light path. Maximun permissible inclusions are listed
below (excepting lint):