1 - NGA

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gdnctlc clrcta-sae gnlsctlc squator.
galactic Squator-fl great circle of the
caleefial sphere, incfinad 62° to the cafeef”=l
equator and odncidhw approximately wilh the
cmfer line of the Milky Way, constituting the
primary great circle for the gafectic eyelem of
coordinates. If is everywhere 90° from the
galactic poles. Also called galedk clrcfa.
galactic latltude-Angufar distance north or
eoulh of &re gsbcfic equatoc the erc IX a great
circle through the galactk poles, between the
galectk equster and a peinf on Ihe celestial
s@rere, m.aesurad nerfhwerd or aeufhward from
R %%%7%%’E%3%n%’ ‘b’d
meesuremant.
galactic longltud*Anguler distance eesl of
sidsreal hour angle (SHA) 94.4” abng the
galactic aquatoc the erc of the gskfii equetor
or the angle at the galactic pols between ths
greet circle through ths interaecfkm of the
gelastic aqustor and the celestial aquslor in
Segiffarius (SHA 94.4°) and a great circle
threugh the gstsdic poles messured eastward
from ths grasl side through SHA 94.4” through
360”.
gelactlc pole-On the celestiel sphare, aifher
of the two points 90° fmm the gelactic aqustor.
galactic system of coordlnataa-A n
astronomic morchma syatam using Iatfiude
measured north and aoufh fmm the galactic
equator and longitude measured in tha sense of
incmesing right escensien from 00 to 36oo. The
system was ori inelty dafined such thet the pde
wss et FM = 12‘140m, Dec - + 28”; howevar, in
1958 the Intametionel Astronomical Union (lAU)
infmducad the IAU gafedic eyatern which
defined the pda at FM . 12h49m, Dac = 2724’.
gallay proof—A prod from type on a gellay
bafere h is made up in psgaq also, such proofs.
gal—A unit d mxaleretion equal to 1
oemimeter par aacorrd per second, or 1000
milligsla, used in measuring the actelarstion of
gravity.
gamma—1. (photography) Tha Iengenl of the
MI L-HDBK-B50
G
101
angle wtrkh the stre”ght-iina pat’bn d the
charedaristii curve mkae with the b~axpc6um
asia. If indkefas fhe alcpa of the sfraigM-fine
pertien of Ihe curve and is a measure of tha
exfem of davabprnant and fha czmtresf of the
photograph metarial. 2. (gaomegnetism) A
smell unit M rrmgn~ic tiald itienaify Sometimes
usedindaadbm g the Eertfr’e rrmgrratic fiefd. II
is defkd aa bsing aqusl to lfY5’oerstad. *e
also nanotesla.
gap-(JCS) (imegary) Any specs whara
imagery feifs to meet minimum coverage
raquiremerrta. Thii might be a space not
cxwerad by imsgary or a spece whera the
minimum apecifii overfap was not cbfa’brad.
Sea sko holiday.
Gauas-Kruger grid-See transveras
Mercator grid.
gauaa—A centimeter-gram-second alacfm-
M.S9netiC unit of msgnstic indudion squal to
104 teds. See also tesla.
gazatte=r-An alphebetisal list ol place
nemas giving feature idenlifiition and
geographic ancVor grid motilnates.
Ganaral Navigation Charts-Smell scale
(1:1 ,000,000 or emsller) chsrts designed for
epan sea aurfsce navigat”m. Depktad
information supports voyage plenning, ecaan
navigation, and mifiiery opamliona.
general chart-A nsufid chart intended for
offshore coasfwisa nsvigeticm. A general cherf is
d srrsillar scala then a caest cfwt, but of larger
scele thsn a =iling chert.
ganerel map-(JCS) A mep d small scale
used for ganeml pisnning purposes. See alse
romp.
ganeral proceadon-llra motion of the
equinoxes westward along the acfiplic at the
rate of about 50.13’ par yaer. see afso
Iunleolar pracosslon; planatary
pracasslon; precasslon In decllnetlon;
prsces.elon In right sscenelon;
pracaaalon of the equinoxee.
ganeral-purpose mep–A map wtich
provides “a bmsd range of information and which