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I
step cast in the pmducf ion of relief models.
cessette-(JcS) In photography, a reloadable
container Ior either unexposad of axposed
sensfflzed materfala whch may be removed
fmm the camera or dsrtrmom equipment under
lightened conditions.
Cseelnl map pro]sctlon-A conventional
map pm)ecf~n conefrucfad by computing the
Iengfhe of arcs atong a ealecrad geographic
meridian and along a greet circle perpendicular
to that meridian, and pbffing these as
rectangular coorrfinatee on a plane.
MIL-HDBK:850
Ceselnl-Soldner maB tsrolsctlon- Similar
to a polycaic map pr6jef%~ excepf that if uses
but one central meridian for a whole series. Best
edapted for north-south belts ad large-scale
maps of small arees.
cestlng—The process 01 reproducing relief
rnedels in plaster or epexy from the terrain base
of the modal, or aftar the surlace of fhe model
has been devaloped. Models are fimf cast
negsflve, fmm filch ❑ny number of poeitive
castings may be made.
casuel error—See random error.
catadloptrlc sysmm-(optics) An optical
svstem containlno both refractive and reflective
eiements. -
catenerv correctlorr-hatrino) Sae eao
. . .
correction.
CathOda ray—1. One of the high-speed
electrons projected in a stream trom the heated
cathsde of a vacuum tube under the propulsion
of a afmng alecrric field. 2. A stream of celhoderey
efecfmns
cathode-ray tube-A vacuum tube in which
cathode rays, uauafly in the form of a elendar
beam, are prolecfed upon a ffuorescerrf screen
fhaf serves aa an errfica!hode where the rays
produce a luminous spot.
csthode-The elecfmde at which electrons
enter a devbe fmm the external circuit.
cetoptrlc system-(optics) An optical system
in which all elements are raflecfive (mirrors).
cautlona~ note-lnformallon cafllng special
attention to some fact, usualfy a danger area,
38
shown on a map or chart.
celestlel coordlnataa—Any set of
coordinates used to deline a point on the
celestial sphere.
celeatlal aquator aystam of
coordlnatas—A sel o? cefestial coordinates
based on the celestial equator as lfre primary
greaf circle; usualfy dacllnatbn and hour angle
or slderaal hour angle. Afao calied aquator
ayatem; equatorlaf system; aquhtoctlal
eyetam ot coordlnataa.
caleeflal equator-Tfre great clrcfe on the
miestial ephera whose pJane Is perpendiilar 10
the axis of rotation of the Earth. Also cafied
equlnoctfal.
celesliaf fix—A position established by means
of observation on one or rnera celestial todies.
cefesllal geodeey—The branch of geodesy
which utifizes obsewalions of near C81aS.til
bodies, including Earth satellites, to datermins
fhe size and shape of the Earth.
celeatlal horizon-That circle of the celestial
sphere formed by the interjection of fhe
celestial sphere and a plane through the center
of fhe Earth and perpendicular 10 the zenith
nadir tine, Also caffed rational trorlzon.
celeetlal latltuda-Anguiar disfanca north or
south of the acllptk; fhe arc of a circle of Iafiiude
between the ecliptic and e point on the celaefial
sphere, measured northward or aoufhwati fmm
the ecliptic lhrough 90°, and labeled “N- or ‘Sto
Indicate the direction of measurement. Also
called acliptic iatitude.
cefestlal fine of poelllon-A fine of PrMflon
determined by means of tha observation of a
celestial body.
cefeaflal longituda-Angular distance east
of fhe vamal aquinox, abng the ecfipfic: the arc
of fhe ectiplic or the angle al the ecliptic pole
between the circle of latitude of the VetTIal
equinox and tfre circla of ialifude of a point on
the celestial sphere, measured eaafward fmm
the circle of Ialilude of the vernal equinox,
Ihrough 360°. Also called acllptlc Iongltude.
celeetlal mechanlca—The study of Iha
fhaory of fhe motions of celestial bodias under
Ihe infiuance of gravitational fiefds.