The imaginary sphere whose center is the center of the Earth and on which the fixed stars, planets, Sun, Moon, and the zodiac are located.
A huge sphere centered on the Earth, which provides a convenient way to fix a coordinate system on the sky. Every object in the sky can be found by knowing its declination and right ascension. The Celestial Sphere
Apparent sphere of the sky, a sphere of large radius centered on the observer. Directions of objects in the sky can be denoted by their position on the celestial sphere.
The sphere of heavenly objects that seems to center on the observer.
The celestial sphere is simply another name for the apparent sky. We always see one half of the celestial sphere – the dome of the sky overhead. The other half is hidden by the earth beneath our feet.
An imaginary sphere surrounding the globe that contains the sun, moon, stars and planets.
The imaginary sphere on which the the night sky is seen to be projected on.
The visible, seemingly spherical surface that appears to surround Earth and to be centered at the observer.
An imaginary sphere of infinite radius concentric with the Earth, on which all celestial bodies except the Earth are imagined to be projected.
From ancient times, the supposed spherical shell surrounding the Earth and containing all the stars, planets, the Sun, and the Moon.
An imaginary sphere surrounding the Earth where the sun, planets and stars are, a 3 dimensional map of the universe. See Celestial Coordinate System page.
the imaginary sphere centered on the Earth to which the stars are affixed.
imaginary sphere of extremely large size around the Earth on which the stars appear to be placed.
An imaginary sphere, centered on the observer, which is used to represent the positions and motions of the heavenly bodies.
a projection of what the sky would look like if the stars were attached to a sphere surrounding the earth
The projection of space and the objects therein onto an imaginary sphere surrounding the Earth and centred on the observer.
sphere in the heavens on which the celestial motions are considered to be moving for the purpose of positional measurements from earth. It is far enough away for the earth's size to be negligible in relation to the distance of the stars, so that all observers can be considered to be at the centre of the celestial sphere.
an imaginary spherical "movie screen" upon which all stars, planets, and other bodies in space can be thought of as being projected. Coordinates on the celestial sphere are specified in degrees of declination and right ascension, roughly analogous to latitude and longitude coordinates on Earth's surface. See Celestial Sphere Figure.
An imaginary sphere surrounding the Earth, onto which we consider all other celestial objects to be pasted. Stars change their positions on this sphere very slowly. For most purposes, in the time scale of decades, they can be considered fixed. The movement of the stars that we see nightly can then be thought of as a uniform rotation of the Celestial Sphere.
The celestial sphere is an imaginary sphere which surrounds the earth. The sphere rotates about an axis, which runs through the centre of the Earth, in the opposite direction to the real motion of the Earth. The stars on the sphere rise in the East and set in the West. The time for one rotation of the sphere to take place is one sidereal day. Positions of the stars are fixed on the celestial sphere and are given in right ascension and declination. Planets, and the Moon and Sun, change their positions on the celestial sphere with time. See also celestial pole and celestial equator.
imaginary sphere surrounding Earth; model of the sky
The imaginary sphere of stars surrounding the Earth.
An imaginary sphere of infinite radius on which celestial objects appear projected.
An observationally practical model of the sky as a sphere with fixed stars that rotates around the Earth.
A two-dimensional imaginary illusion that is used in describing the exact location of all celestial objects (planets, stars, galaxies, etc). All stars (etc.) are very far away, some further than others but to the eye they all appear to be equally distant. So imagine that the Earth is at the center of a hugh sphere, maybe inside of a monster basketball, and time and all motions of the Earth have stopped. All of the objects in the sky are now marked ( maybe with white paint) on the inside of this giant, dark sphere. Now the coordinate lines of the Earth (which are imaginary but yet real also) such as the equator, north & south pole, horizontal lines of latititude (see Declination) and vertical lines of longitude (see Right Ascension) are projected outward and also marked (with white paint) on the inside of the sphere. Remember that this sphere with all of the marks (stars, etc.) & lines (coordinates) on it never moves or spins. Now start the Earth back to its normal motion and imagine the Earth rotating and moving around the Sun against the Backdrop of the inside of the now marked sphere. This explains the motions and positions of all the stars, etc. that we see.
An imaginary sphere surrounding the Earth where the sun, planets and stars are, a 3 dimensional map of the universe. Click here for more about the celestial sphere.
The projection of the Earth into space, in which one imagines that the stars are drawn on the inside of this sphere.
an imaginary sphere surrounding the universe on which terrestrial, solar, and celestial coordinates are projected. When these projections are terrestrial, they are preceded by the word Celestial (e.g. Celestial North Pole).
An immense sphere surrounding Earth, to which the fixed stars seen at night appear to be attached. Although strictly speaking such a sphere does not exist, it is often used as a convenient tool for mapping the position of stars and other heavenly bodies. In a similar way, although it is clear that the apparent rotation of the celestial sphere is really due to the Earth rotating around its axis, that rotation is often used for convenient description of apparent motions such as the rising and setting of stars.
The sky as a hemispherical dome when observed from any point on Earth. Celestial objects in view depend upon the date, time and observer's latitude.
The apparent sphere of infinite radius having the earth as its center. All heavenly bodies (planets, stars, etc.) appear on the "inner surface" of this sphere and the sun moves along the ecliptic.
Imaginary sphere surrounding the Earth, to which all objects in the sky were once considered to be attached.
The apparent sphere of sky that surrounds the Earth; used as a convention for specifying the location of a celestial object.
The projection of space onto the night sky, an imaginary hollow sphere of infinite radius surrounding the Earth but centred on the observer. (First postulated by Ptolemy.) It is the basis of sky charts, and the celestial co-ordinate system. The coordinate system most commonly used is right ascension and declination. The sphere itself is split up into arbitrary areas known as constellations.
the apparent sphere of the sky; an imaginary sphere of immense radius centered on Earth often used to plot the coordinates of objects in the sky
An imaginary sphere around the Earth on which the stars and planets appear to be positioned.
Looking up into the sky, it is the imaginary dome where all stars appear to be fixed. All planets, except earth, appear to travel in front of this backdrop.
An imaginary sphere of infinite radius, on which the stars appear to be placed.
The sky envisioned as a (hemi)sphere at infinite focus. This is how it actually appears, although in reality all observable objects are at widely varying distances.
All celestial bodies are assigned a two-dimensional coordinate location on the surface of this imaginary sphere.
The celestial sphere is an imaginary sphere whose center is the Earth. This sphere is used by astronomers to map celestial objects.
Imaginary sphere surrounding the Earth to which the stars, planets, Sun and moon seem to be attached.
imaginary sphere, in the centre of which the observer is located, on the surface of which the celestial bodies are projected, as well s the reference celestial co-ordinates.
The apparent surface of the imaginary sphere on which celestial bodies appear to be projected.
an imaginary sphere of arbitrary radius upon which celestial bodies may be considered to be located. As circumstances require, the celestial sphere may be cantered at the observer, at the Earth's centre, or at any other location.
The sky as it appears to an observer.
An imaginary sphere of very large radius centered on the earth, on which the celestial bodies appear fastened and against which their motions are charted.
A coordinate system similar to Earth's latitude and longitude used to locate planets, stars, star clusters, nebulae and galaxies. The celestial sphere is centered on Earth, and it includes the celestial equator, the north and south celestial poles, and lines of right ascension and declination.
The conceptualization of the infinite heavens as a sphere revolving around Earth, based upon the part of the skies visible from a point on Earth.
The imaginary sphere of the sky, centered on the Earth, and on which the Sun, Moon, planets, stars, and galaxies can be visualized as all at the same distance from the Earth.
An imaginary sphere of very large radius surrounding Earth on which the planets, stars, sun, and moons seem to be moving.
The imaginary sphere, with its centre being the centre of the Earth, onto which the zodiac, constellations and planets are projected.
This does not actually exist. Early humans believed that stars were fixed to a crystal sphere in the sky, at a great distance from Earth. This is because there is no sense of distance in the night sky and the stars always seemed to be fixed in position relative to each other. The idea is a handy one when dealing with positioning and angles between objects in the sky. See also celestial latitude, longitude, azimuth.
In astronomy and navigation, the celestial sphere is an imaginary rotating sphere of "gigantic radius", concentric and coaxial with the Earth. All objects in the sky can be thought of as lying upon the sphere. Projected, from their corresponding geographic equivalents, are the celestial equator and the celestial poles.