CELNAV (PRELIM) Flashcards
major planets only _ are normally used in
navigation
Venus, Mars, Jupiter and Saturn
apparent positions of the planets in relation to other members of the Solar System
PLANETARY CONFIGURATION
whose orbits lie inside that of the earth like Mercury and Venus.
Inferior planets-
whose orbits lie outside that of the earth like Mars, Jupiter, Saturn, Uranus,
Neptune (and Pluto)
Superior planets-
Inner planets-
Mercury, Venus, Earth and Mars
Outer planets-
Jupiter, Saturn, Uranus, Neptune (and Pluto)
Mean distances of the planets from the sun ranges from_
67 million miles for Venus, 886 million miles for
Saturn, the period required by each complete a revolution around the sun carry from about 225 days for
Venus, to 29 ½ years for SaturnConjunction (of a body)- is the position on its orbit when it has the same celestial longitude as the sun.
is the position on its orbit when it has the same celestial longitude as the
sun.
Conjunction (of a body)-
if the planet is between the earth and the sun
Inferior conjunction-
if planet is on the opposite side of the sun to the earth
Superior conjunction-
is the difference between the longitude of the sun and that of the body or
the angle between the lines from the earth to the sun, from the earth to the celestial body
Elongation (of a body)-
the sun, moon and earth are in line and the sun and moon are on the opposite. Occurs
at Full Moon
Opposition-
the sun and moon are 900 in relation to the earth. Occurs at First Quarter and Last
Quarter
Quadrature-
Elongation:
New Moon=
First/Last quarter=
Full Moon=
New Moon= 0 degrees
First/Last quarter= 90 degrees
Full Moon= 180 degrees
is the position of the moon’s conjunction when the moon has the same celestial longitude
as the sun.
New Moon-
Age of the moon is 0 day
New Moon-
the moon’s elongation has increased and parts of the moon’s illuminated disc is visible
from the earth.
Waxing crescent-
It appears as a crescent with cusps or horns turned towards the sun.
Waxing crescent-
the moon reaches quadrature. The half of the moon toward the sun is illuminated.
First Quarter
Age of
the moon is 7 ¼ days.
First Quarter
more than half of the illuminated moon is visible from the earth
Gibbous-
the moon is in opposition. The whole of the illuminated half of the moon is facing the earth
and the moon appears as full.
Full moon-
Age of the moon is 14 ½ days.
Full moon-
After full moon, the visible moon decreases in size, the moon again becomes
Gibbous-
the moon is again in quadrature. The half of the moon toward the sun is illuminated.
Last Quarter-
Age
of the moon is about 21 ¾ days
Last Quarter-
the sunlit areas appear on the eastern side of the moon
Waning Crescent-
the time when the size of the visible moon is increasing
Moon waxing-
the time when the size of visible moon is decreasing
Moon waning-
from new moon to the next new moon.
Lunation-
the full moon occuring nearest the autumnal equinox.
Harvest moon-
the full moon next following the harvest moon.
Hunter’s moon-
the line separating the illuminated and dark portions
Terminator-
The motion of the bodies of
the solar system relative to surrounding stars is called
space motion
The earth itself is one of these moving
bodies, the motion of other bodies as seen by an observer on the earth is called
apparent motion
If the earth were stationary in space, any change in the position of another body, relative to the earth,
would be due only to the motion of that body, this motion is called
absolute motion
