Axis
The Earth's rotation axis is titled at 23.5 degrees to the terminator between night and day.
axis
An imaginary straight line through a celestial body, around which it rotates.
Definition: Axis: An imaginary line through the center of an object around which it spins.
Space Tragedies9 Planets in Nine DaysAstronomy 101
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Optical axis
In an optical system, the optical axis is an imaginary line that defines the path along which light propagates through the system.
Earth's Rotation Axis
The Earth's rotation axis is not fixed in space. Like a rotating toy top, the direction of the rotation axis executes a slow precession with a period of 26,000 years (see following figure). Pole Stars are Transient ...
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AXIS
An imaginary straight line around which an object spins.
ATOM
The tiny building block that makes up everything.
Axis- the imaginary line through the center of a planet, star, or galaxy around which it rotates; also, a similar line through a telescope mounting
Bar- equals 0.987 atmosphere = 1.02 kg/cm2= 100 kilopascal = 14.5 lbs/inch2 ...
Axis
also known as the poles, this is an imaginary line through the center of rotation of an object.
Azimuth
the angular distance of an object around or parallel to the horizon from a predefined zero point.
axis (of the Earth's rotation) or polar axis: the line running through the true North and South poles about which the Earth rotates.
Axis: Bold as Love is the second studio album by The Jimi Hendrix Experience.
Axis
Theoretical straight line through a celestial body, around which it rotates.
Axisymmetric Collapse ...
3-Axis: Alternatively, a spacecraft may be designed for active three-axis stabilization. One method is to use small propulsion-system thrusters to incessantly nudge the spacecraft back and forth within a deadband of allowed attitude error.
MAJOR AXIS - Longest diameter of an ellipse; the line from one side of an ellipse to the other that passes through the foci.
Polar axis The axis around which a celestial body rotates.
Proper motion The small change in position of nearby stars due to motion across the line of sight (measured in seconds of arc per year).
Polar Axis
The axis of a telescope around which the celestial sphere rotates
Poor Galaxy Cluster ...
Major Axis - The axis of an ellipse that passes through both foci. The major axis is the longest straight line that can be drawn inside an ellipse
Mantle - The part of a planet lying between its crust and its core ...
polar axis: The axis around which a celestial body rotates.
poor cluster: An irregularly shaped cluster that contains fewer than 1000 galaxies, many spiral, and no giant ellipticals.
Polar Axis
The axis of an equatorially mounted telescope that points towards the Celestial Poles and is therefore parallel to the Earth's axis of rotation. [McL97]
Polar Motion ...
Axis
An imaginary straight line on which an object rotates.
Weak microwave radiation coming from space in all directions. It is believed to be the remnant of the Big Bang.
Axis (plural = axes) In astronomy, the imaginary line through the poles about which a body (planet, star, moon, etc.) rotates.
B
Baryon Protons and neutrons ...
Axis
An imaginary line through the center of an object. The object rotates around this line.
BATSE (Burst and Transient Source Experiment) ...
AXIS
An axis is an imaginary straight line around which an object, like a planet, turns. The Earth's axis is a line that goes through the North and South Poles.
z axis:
x' = x * cos(a) - y * sin(a)
y' = y * cos(a) + x * sin(a)
remember that if you are using these formulas as part of a programming exercise, z' is NOT the same as z so if you say something like: ...
RA axis is definitely quieter with the steel gears
DEC axis seems about the same as the before
The EZ-Clutch seems to be a good investment - just a very light touch on the DEC knob and we're locked down.
Second impressions: ...
one axis of the altazimuth coordinate system. It is the great circle on the celestial sphere midway between the observer's zenith and nadir; it divides the celestial sphere into two equal hemispheres.
The axis of rotation is inclined to the orbital plane at an angle of 24.935 , and, as for the Earth, the tilt gives rise to seasons on Mars. The Martian year consists of 668.6 Martian solar days (called sols).
the axis inclination (set at a default value of 23.5°)
orbit eccentricity (set at .017)
perihelion's day after the winter solstice (set at January 3 - December 21 = 13) ...
The axis of the flashlight is also the axis of the cone of light. Aim the beam perpendicular to the wall to get a circle of light. Slant the beam: an ellipse.
The axis of Mars does not point toward Polaris, our North Star, but is displaced about 40° towards Alpha Cygni.
The axis of an equatorial telescope mounting that is parallel to the earth's axis of rotation.
polarization - (n.)
The arrangement of electromagnetic waves so that all the planes in which the waves are oscillating are parallel to each other.
The x axis represents distance, and I would be some varying quantity (for instance air pressure for a sound wave or strength of the electric or magnetic field for light), at a given point in time as a function of x.
A three-axis accelerometer will output zeroâ€'g on all three axes if it is dropped or otherwise put into a ballistic trajectory (also known as an inertial trajectory), so that it experiences "free fall, ...
Tilt of axis (degrees)3.13
Orbital inclination (degrees)1.308
Equatorial surface gravity (m/sec^2)22.88 ...
Triton's axis of rotation is also unusual, tilted 157 degrees with respect to Neptune's axis (which is in turn inclined 30 degrees from the plane of Neptune's orbit).
Magnetic axis tilt relative to rotation axis
11.5°
Mean surface temperature ...
Uranus's axis is tilted by about 90 degrees from the vertical, meaning its axis lies more or less in the plane of the solar system - Uranus spins on its side.
Mercury's axis is almost perpendicular to the plane of its orbit around the Sun. This means that the Sun's rays always strike at a very shallow angle to the surface at the poles and the floors of the deepest craters are never exposed to sunlight.
semimajor axis
The semimajor axis of an ellipse (e.g. a planetary orbit) is half the length of the major axis, which is the line segment passing through the foci of the ellipse with endpoints on the ellipse itself.
Semi-major axis greater than 1.0 AU, perihelion less than 1.017 AU.
Amor group
Semi-major axis greater than 1.0 AU, perihelion between 1.017 and 1.3 AU.
The orange axis was the Earth's rotation axis 5000 years ago when it pointed to the star Thuban. The yellow axis, pointing to Polaris is the situation now.
semimajor axis
the average distance of an orbiting body from its parent body
setting circles ...
Because the axis of the Earth points to Polaris, the stars appear to revolve around it at a constant rate. It's possible to tell the time using Polaris and another star (Merak, for example) but you have to know how to correct for the date.
If the time axis is measured in years, the space axis is measured in light-years, and the two axes have equal increments, then light always travels at a 45 degree path on the diagram.
The rotation axis is tilted with respect to the orbital plane by almost 24 degrees, so that both Earth and Mars experience significant seasonal differences in the amount of sunlight falling on a hemisphere during the year.
The vertical axis displays the luminosity of the stars. This is either as a ratio compared with that of the Sun or as absolute magnitude, M.
semi major axis (a):
Measure of the size of the orbit (mean between perihelion and aphelion distance). It is related to the orbital period by the third law of Kepler (the cube of the semi major axis is proportional to the square of the period).
Semi-major Axis Half the distance across an ellipse measured along a line through its foci.
Sidereal Time The hour angle of the First Point of Aries. It is time measured with respect to the stars. See the tutorial on Time.
Name Semimajor Axis (km) Period (days) Eccentricity Inclination (deg) Mean Radius (km) Mass (10^20 kg)
Naiad
48,227
0.294396 ...
1. The Earth's axis is not perpendicular to the plane of the earth's orbit but in fact is tilted 23.5 degrees to the plane of the earth's orbit.
2. The earth constantly maintains this tilt as it orbits the sun.
The semi-major axis of an asteroid is used to describe the dimensions of its orbit around the Sun, and its value determines the minor planet's orbital period.
Earth axis (NASA Thesaurus / NASA SP-7, 1965) Any one of a set of mutually perpendicular reference axes established with the upright axis (the Z-axis) pointing to the center of the earth, ...
Motion aound an axis passing through the rotating body.
rotation curve
A graph of orbital velocity versus orbital radius of stars in the galaxy.
Spot Diagram On-Axis (zero offset)
Spot Diagram 0.0417 Degrees Off-Axis (5 arc-min FOV)
Spot Diagram 0.3 Degrees Off-Axis (36 arc-min FOV) ...
It turns out the axis of the spinning gyroscopes drifted, but just barely.
Sketch of the Gravity Probe B spacecraft. Credit: NASA/Stanford University ...
10. The vertical axis in the HR diagram corresponds to
stellar temperature
stellar diameter
stellar distance
stellar luminosity ...
The the semi-major axis of an orbit ellipse is half the length of the major axis. For solar system bodies, the value of semi-major axis is typically denoted by a and expressed in units of AU.
Earth's rotational axis points in the same direction relative to the stars, so that the North Pole points towards the star Polaris. Think of the Earth as a spinning top, tipped over to one side.
Earth spins on its axis in an anti-clockwise direction and takes 23 hours 56 minutes to rotate (turn) once.
Because the Earth's axis is precessing (like a spinning top wobbles around), Polaris is only temporarily at the North Pole. In about 14,000 years, Vega will be the North Star and another 14,000 years after that, it will be Polaris again.
 See also: Earth, Sun, Orbit, Light, Time
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