1 - NGA

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and with dl tfVSS SXES tfii in a pk’t13
perPczMkufar 10 the fins d ffiiht. Most SSM
esssMea dthkdas@n wemmfan’ad tOSS
trlmatrogorr camera because of the
wideepreed uaega of the MatrogIxI lens in earfy
trlcamara photography.
Mmotrogon photo mphy-Saa fan
1
camsm photogmp y.
trlmmlng and rnountlrrg dlagrmrt-A
&eroh * how the prints of a tmnsfermad
muft!!ldans @mtogmph should be corrected to
oMaino h effect, a phdegm@r rrbsda bys airt@e
Iana. lhekhrrn=fionieghfaintitirnr of
d-m mfermd to tha fduckd rnadta on the
photograph, end k the mauk of the salibretkn
test fer ha particular samem used.
Tropk of Cancer—The nerthem parallel of
decfirrstion, approximately 23”27 from the
celaetii equstor, raeched by the Sun at ils
r-neximum dacikdkn, or the ocrreapondng
parallel on the Earth.
Tropk of Caprico~The aeuthem parallel
of declination, Spproxirnatety 23%?7 from the
--- ~W SUuator, reached @.lha Sun at ils
mesimum .3eol@stim, or the corresponding
parallel on the Earth.
tropical month-The average period of the
revolutii of the Meon Mrcmt the Earth with
I mamd 10 the vernal tmuinox, eppmsirnetefy 27
1/3” days.
tropkal yeer-The intervel of time between
k wcumaive peaaogea of the Varnel equinox
by rha Sun. The tmpics+l year is the yaar of the
aaaama. and the MS of ttm sorwetimnal
sekndsr year. Ake celled ●stronomic year;
squlrtootkl yaec natural yaec solar
year.
tropopttuae-(JCS) The trenailbn zone
between the atratosphare and the tmpoe@era.
The tmpcpauaa normally cxxwrs et en aftiiude of
atmut 25,000 to 45,CKN feet in pokr afd
temperate zones, end at 55,0M feet in the
lrepka. See also atmoriphera.
troponphars+JCS) The kwer Iayara of
atmcaphem, in wtich the ctwnge of
temperature with halght is relatively large. It is
the region where ckwds form, oonvastiin “m
ediva, and mtzing ia cordnuoue and more or
leas somplete. See ak.o atmosphara.
MI L-HDBK-850
260
tropoapherk ecMter+JCS) The
Propegm’m d radii waves by scattering as a
* d iIIEWtikW or d~inuibs in the
physical properties c4 the tmpOs@m.
trough compasa-See daalinatoim.
Troughton level-An Engfkh inatmrnant
having thaq)iritteval PamW8ntty atteched to
the top of the klhcopa tuba
truo ●ltttuda-1. (JCS) The height of an
aimmft as maaaured fm.tn mean see level. 2
The add afIiiwte of a oskslii body above the
Sakstial horizon. Akc czdkrt observed
●ltltuda.
truo empllWla-Ampktude relative to true
nest or weet. See also amplltude.
true anomsly—Sefr anomaly, definition 3.
true azlmuttr-The horizontal dkestion of any
line measured clc-drwisa from true rsx’th.
true bearln~The horizontal angle between
the meddkn line ard a tine en the Earth. Tne
term true bsartng ia used in many cd the earty
dessripticms of knd boumianes in the United
states. h is associated with tma north. derring
to the direction ef the north @nt aS detanmined
by astmrrornk cbserwliens. If an eatrcrrcsmicaliy
determined bauring is used, howemr, the term
astrsrnomk boarlng ie preferred over truo
besrlrtg.
true dsprasslon ●rglxl%a setting of the
tique cameras In the pfmt~ abcratf W*
rebdion to the trus frarizon. It k defined by a my
from the exposure statism ttwm@h the principal
point d the obhque phc&gmph and a ray to the
tme hol-kon.
true dlmctlon-herkotial direstkm sspreeeed
as angular dktance fmm true nrnth.
true arror—See resultant error.
true horizon—(JCS) 1. The boundary of a
horizontal plane passing through a point d
vision. 2. In pho!ogrammetry, the boundary of a
horizontal plane pesdng Ihreugh the
pemp-~e center of a lens eyetem. See al~
horizon trsce.
true llrm-A line of constant b-ring (rhumb