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MIL-HDBK-E150
z+xis—in a threa4me rvzional rectangular
mxdhste system. the axE3 & rdemnca xerm tltna-Tha kxaf meen time of a
ttd is pwpendkwlar to tmfh the x- and y- preference zene. See afse thne zone.
arms af their @m 0! Wwsec4ii.
zoom systOrn-Saa pmrcretlc systam.
z-rnotlon-Movement of e atereepfotting
prmjecfor in a verl~l dfmcfien. ZUIU tlma--see Untveresl TIma.
z-ecale-(JCS) On an oblique photogmph,
fheecale ueedincalcufaIing tha height of
~ e@cL Afao, the rmrne given to th~
method of height delemrinstion.
z41me—See Unlveraal Time.
z-value data pelnta-Oata points providing
a value perpandiiuIer er norms] 10 a
specified surface (elevaticm).
zenitfr-Thet point of the celestisl sphere
vefi”keliy overhead. See alse geecentrlc
zenith; geodotlc zamlth.
zcnlth engie-see zenl!h dls:ance.
zswrlth camor8-A epecief camera se
designed thst its opticaf exie m9y be
pointed ac=xreteiy toward the zentih. 11is
used tor the determinstlen of astronomic
fmeificma by phetographmg the positii of
the z&m, See also photographic zenith
tube.
zenith diatanca-The venicd engle
between the zenith end the object whii is
etmerved or defwd. Zeniih d-rice is the
COI#WMW of the akttude. Afee caffad
zenith sngle. See elso coaltltudm
zenith taleecope-A portable instrument
adapted for the measurement of smsfl
differences of zenfth distsnce, and used in
the detarminstiorr of astronomic latiiude.
Zenhh81 cf’rert-see azlmtrthal chart.
zenlthal map projection-See
azimuthal” map” projoctlon.
zonal hermonlce-The aet of aphericel
hsrmonti that are functions of latitude only
and therefore do nef effect the rotatierml
symmetry of the surface about !@ pofer
exis.
z
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