1 - NGA

norfh-The primary reference direction
relative to the Earth. See also compass
north; grid north; magnetic north;
true north,
No!lce to Mariners—Speci!ic narrative and
graphic correction dala for all DMA, USCG
and NOS nautical charfs, publications and
new information required to navigale. This
information is published weekly. It Is also
accessible on the Network (NAVINFONET)
as inmrporaled in the summary 01
corrections.
numerlcel map—See dlgltal map.
nutatlon In right ascension—Se e
equallon of the equinox.
nutatlon-1. The oscillation of me axis 01
any rotating body, as a gyroscope rotor. 2.
(aslronomy) Irregularities in the
precessional motion of Ihe equinoxes
because of varying positions of the Moon
and, to a lesser extent, ot other celestial
bodies with respect to the ecfiplic.
MIL-HDBK-850
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