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fii) between fwem- ofa aurwy.
tnm nwridlan-A kvm used !0 distinguish the
gmst circle through fhs gsogmphbaf @se trom
MsPtk Metiin, oompsss nreridii, or grid
meridian.
tN@ nori.h-(JCS) The direcibn fnwn sn
observer’s @fiin to the geognrphii North
Pole. Ths north dimdon d any @oun@c
meridiin. ~ term was origiity ep@ied to
aatronomlc narth to daingubfr it frmm
magnetic north.]
true placa-S ee two position.
~No poaftfon-lhe poaifian of a eels.stiaf bdy
sfrer all krmwn mrrect”mns including precoasion
and ntrtefien have bsan rneda. Atso @Jed true
place.
~NO prfmo vertbakl%e vertical circhr
through ths true asat and w- points at the
horizon, es disfinguiahad from magnetic or gfi
prime verficsl through the magnetic or grid esst
end west points, respedhty.
truo sidereal tlms-See ●pparent
●Idoroal tima.
true solar time-See ●pparent solar
tlms.
true sun-See apparent sun.
true vahIe-Thst value of quantii whwh is
=K@Et* f- ftOM arrera. Since lhe errors to
whiih physical measurements are sbjwf
cennof be knewn exscffy, it fotlows thst the true
vafue of a qusntity mvmaf be known with
mactness. In survey ti, ths most probable
vafue ts used es best representing the true
velue of the quantity.
true-to. scale-A cendtiien where map
tW.9sUr~~ts em in exad agreemenf wilh the
afaled msp scale. Stnm atl map projadii
invoke ecxns scale chsnge, the scale b rmt true
at ell @aces on a’ msp.
true-l. Ffefsted to true north as opposed to
ms9~t~ north. 2. Actual, as contrsstad ~h
Wiimua, as true Sun. 3. Related to a freed
point, eitfww on the Emth or in spaca. ss trua
wind; in cOntmSl wilh relat’we, Wlch & retsl~ to
a moving point. 4. Corrected, as true effitude,
S. One of two alternsta velues (TrueJFalse)
MIL-HDBK-850
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used in 6odeen bgii.
turning point (TP~ poiti on vhii beth a
minus sighl (icmsighf) ad a pfus Sigfd
~) are taken on a &ne 0( dwOd bveta.
Abe, in tcfqmphii Surveys, any point m Whldl
fhelodie heldwhiletfre” ImtNmmtb movedto
emthar 6idon. Thaee turing pohfe are often
msrkedfor futlxaues aetieorcfreok points.
turning point pin-A deal pin about one foot
brig. In Ievefing Operstbrs, the tumhg polnf Is
driwen info the ground where it is neceaaery to
eababfkhapointthetw iUb asiaMe in elevation
fsrasfrod perfodoftlme. Whenkfusaervedtfs
Usefulness at one pokd. if is nanoved and
canied by the rcdrrrm for subaequad reuse.
turret grmrer-A acriing instrument wlrfch
permits the use of points of several weights
intsrchsngeebfy without the inoonvenlence of
intenupfing the acriing 10 rt@ece pdnts. The
turret head ia revolved to position tb cfeafmd
poht, and a.cribhg is resumed.
tumhe-An ink for dmftirrg printing amss on
Iithagraphiipfates.
tuschhrg-llw operst”wn of adding wefk to the
image on o prsas plate, mrrecting Iinaa and
Ietfetfng, and addii aotids by means 01 tuschs.
Also cslled lithographic dmttlng.
two-base mathod-A t=hnlque of
bsmmetrb fevating ufifiing ffrrw berornefera.
TW bsromatera, one high ssfabtii over a
known elavatbn, and me bw estebJbhsd wet
a known elevation, and a roving bemmetw
operating betwaen the two fmown poslficms.
High end low barometers are reed and
recorded, hith tempemture, evety fwe minutes.
The roving barometer and terrperafum ere reed
and recorded at each ststion omupbed. Osta are
reduced to position end elevstion by offlx
~mP@f~n. The only bsmrnatrb leveling
methad sble to consistently pmdum emxs fees
Ihsn *1 meter. See afso fly-by-method;
Ioapfrog method.
twebody orbit-llre nrotien of e point msas
in the prssence of the gravitational attraction, of
another point ~, and in lhe absence of any
other forces. Thii wbii is usualfy an eftipse, but
msy be a psrsbola or hyperbola,
two-body problenr-That problem in celastial
mechanics which tr,sats of the relative motion or
of two-peint msssss under their mutusl