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one-to-one (1:1) copy-See contact
Size.
opacNy-See donslty, defintilon 1,
opaqu~l. Not transmitting fight. 2 No!
transmitting the particular wavelengths (whbh
MSY w ~Y ~t bS visible) whiih affasf given
photosensitive metariefs. Thus, e substance
msybacpaque toaernscobrs end notto
others. Ii sway be visually @nsparent, yet
adiniselfy opaque. 3. A matetfal epplbd to
emas of a negative to make il opeque m those
eraas. 4. To appfy e materiel w bbckeut.
open ●d traverse-See opm trevarsa.
open eystsm (OS)-t. Any system thal
interacts wiih KS envimnmant through inpul end
output. An epan system is eble to edspt or
edjust to shsnges in the environment in order 10
continue its axisiense. 2. In sorqnrters, en
epan sysiem has detailed published oparaling
inetrudiom, hsrdware end software daacriptiorrs,
end interface diagrams enebhng users and thti
party vendors 10 add to or rrmdify the system to
adspt i! to the usats apacifc needs, See also
GOSIP.
open tmversKA survey traveme which
bsgins from e station of known or edcptad
position, but does not and upon s known or
edOfJfd station. Also called opan end
traverse.
open window Pr=oss+csflography) A
method of preparing sobr separation negatives
or positives W peeling an opaqua stratum from
its base in the desired areas. It is normally used
for prepering large areas covered by vegemtion
~ OPen WSler. * else sneak, definition Z.
operation map-(JCS) A map showing the
bc.stbn and strangfh of friendly forces invofvad
in an operation If may indtcete predicted
movement and katien of enemy forces.
Operational Navlgetion Chart (ONC)-
Ths stenderd worfdwiie small-scale
(1:1 ,000,000) aerenautbel chart serbs. It
oontains sartographm data with an eerrmsufbsl
overprint depicting obstrucfioms, aarodromes,
etc., designed for medium attiiude high-speed
visual and radar nevlgetion, Also used for
mission pfanning/ensfysis and intelligerrse
briefings.
MIL-I-IDBK-850
oporatlotml grid-A grid in currant
oparafionsl use. Genaralfy this weuld be the
prafermd grid but oc.ukl be a pmvbusty
pwmioed grid.
opemtfonal llbrarlaa-A DMA approved,
sefesfive date file sonskting of axim sc@se of
originafs, dupkale copies. oompufar fxinted
catalogs, etc., obtainad from any daeignelad
DoD Iitsary or from other nsfioneliy designated
brariis within the non-DoO aganoies. and
maintained in a DoD MC&G agansy for he dtrecf
use in accor@ing assigned production
mbsions. General reference pubfbatbns sush
as dbfibnsries, gbseariee, atlases, pariodiils,
etc., are axsluded from cxwtfmla e@ad to
oparstiorml libraries.
oporatlonel system-A system that has
bean devebpsd, verified, and is being operated
under the auqkes of a unified er specified
commend.
OPpOsltl O*l. The situatien of tvm celestial
bcdas having either celestial longitudes or
sideraal hour sngles differing by 180-. The term
is usualiy used only in’ relalion to the position of
a pfanet or moon frcfn the Sun. 2. The eituation
of two periodic quantities differing by half a
cycle,
optical axle-(.fCS) In a lens element, the
straight fine which passes !fsmugh the ~ars of
curvature of the lens surlacae. In an s@ical
system, the fine formed by the coinskhg
principal axes of lha series ef optical elements.
Also sallad axis of lens; Iena SXIS;
prlnctpal ●xis.
optical baee-llne maasurlng ●pparstua—
A bass apparatus oompoaed ol bare wfvxre
lengths are defined by distances between fines
at or near their ands, wfrich are cbserved by
suitabfy mounlad and adjusted mkmxoopas. In
using any optkal bsselina measuring apparatus,
the -Ions of the bars are c=xrfrdfed bv
mic&cOpas on stsbfs aup+x.rtt whims Ads
fines may be brought into coincidence with the
fiiucisl marks on the bare, eithw by adjusting a
bsr or a micmscepe.
optical canter-The peinl of intersection of
lines which represent within the lens tbse rays
whose amergant directions are parallel to their
reepactke “midant dkecbne. lhb point lies on
Ihe eptical axis. An clique ray, even if it pssaaas
through this point, undergees a bngitudinal
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