5-2
5-1 ZE ROIN G OPE RATIO NAL d EFECT S
Operational defe cts refer to the re liability of t he image inten-
sifiers and are an evidence of instabil ity. Their identification
shall be a valid reason to immediately refuse to accept the ATN
PS-15. These i nclude shading , edge gl ow, flash ing, fli ckering ,
and intermittent operation.

A. SH AdIN G

If shading is p ersistent , you will no t see a fully c ircular im age
(Figu re 5 -1). S hadi ng i s ver y dar k an d you can not s ee an imag e
through it. Shading alw ays begins on the edge an d migrates
inward eventual ly across the entire image area. Shadin g is a
high contr ast area with a di stinct line of de marcat ion. Con tact
ATN or po int of pu rch ase for w arra nty /re pai r pr oced ure s.
Figur e 5-1
Shading
NOTE
Make sure the shad ing is not the res ult of improper exit pupil
position.