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obltqua sphese-The cdestial ephem as it
-m !0 BfI observer bsfween the Equator
and the pole, wltera caiaatial bodie4 appair 10
rise obliie!y to the horizon.
obllqulty of tho acllptic-Tire acute angle
bafween the ptane d the ecfiplk (the pkene of
the Earth’e orbff) and the ptena of the cefesfiaf
equator.
oblffemtsd corner~n obfifereted camar ia
one al whine point there are m ramaining
traces of the rnmsument or tts a~aaoriea, but
whoaa location his bean perpatustad, or the
pckt for whiih may be mcovomd beyond
reasonable dcwbt, by the acts and taafirmny of
tha intersected Iandownars, compatant
aurvayom, or other quafiii &cal .sulktorii&, w
witnesam, of by awns acceptable recent
evidence.
obsarvntion equatlort-An adjustment
aquet”bn wherein variables representing
cerredkms to approxknetions of the unknown
pammetera, as well as vstiebles rapmsenting
adjustments to the observelions, remain in the
~tbps. + 1S8S Squrima adjuatnremt
emp~YW3 th?s type cd equstiom is said to be by
the obaafvatron equations methed, m variation
of parameters method, as opposed to the
condiion equations method.
obs*rv@lon-See obsarvad value.
obswvod ●ffltuda-Carected sexienl
ahilde; angutar d~enca to the center of a
celestial bxly ebove the horizon, mrmcled for
instrumental ermm. pamosrel error, dip.
relredion, and eemidiemeler end paellex if
neceesery. See also truo dfitude.
observed angla-An engle obtained by direct
instrumental cbeervaticm A measured angle
Wfsiih hes bean corrected for bud condiiiens
only et tha point of obsenfation, is cmaeidemd
an observed engla.
obaarvod gravity ●nomafy-See gravity
●nomaly.
obaorvad gmvfty-The value of grsvlty at a
station ee determined fmm e gravity metar, a
pandulum, or an instrument timing free falling
bodies. The gmvity ok4eind is eilhar relattie or
ekolute according to the apperatua used to
make the maaauramanle.
MIL-HDBK-850
obaorved valua-A value of a quantify that is
okieined by instrumental maeaumment of the
qusniity. The term observad valus La often
a@iad to tha value of a quantify tied horn
inefrumenfel nreeaunmrant nftar corradons
have hsen applied for eyefamatic errors by
some methcd d adjustment.
obaolata cfsatt-A chart which does not
contain the tahst nevigafionsl information,
occuftatlon-1. (astronomy) The
di~pearenca of a cefesfiel body behind
amtfwr body of larger eppmenf size. When tha
Moon paasas between the obaasvar and a star,
the sf.sr is said to be occuttad. 2. (aufvaying)
Name appfiad to a geodetic survey technique
which employs the primiple c4 ocdtafion where
repeated cbeervations are made on an
unknown position, accurstefy timed with aimllar
obsewations at another unkmwn sfatiin, snd
msfhemsticelly reducing these date to
detemrine the exact geodetic poailii d the
unknown stations. See elm star occultation
method.
occupy -(aurwying) To sat a surveying -.
instrument over a point for the purpose of
making observations,
ocaanographlc ststlon—An observation
point in ocean fmm wiich meemgrephii
obearvet”ws am taken.
oceanographic survey-A study or
examinat”mn of renditions in the ocean or any
part of if, with reference to animal or plant ~da,
chemical elements present, ie~atum
gradients, etc. Also selled msr’hm survey.
oceanography-1. The study of the W,
emtxecing and integrating all krmwiedge
pertaining to the me end ifs physical
boundaries, the chemistry and phyaica of sas
water, and marine tsioJOgy.
oceanology—Sea oceanography.
octant- type of sextant having a nsnge d
90” and an arc d 4S”.
ocular mlcrometar-A filer micrometer so
ptacad that its wire nmves in the prir+el focal
plane of a taleacopa Also callad ●yaplaoo
mlcromatar.
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