§ 48. Celestial sphere. Basic points, lines and circles on the celestial sphere
A celestial sphere is a sphere of any radius centered at an arbitrary point in space. For its center, depending on the statement of the problem, take the eye of the observer, the center of the tool, the center of the Earth, etc.Consider the main points and circles of the celestial sphere, for the center of which the eye of the observer is taken (Fig. 72). Draw a plumb line through the center of the celestial sphere. The points of intersection of the plumb line with the sphere are called the zenith Z and the nadir n.
Rice. 72.
The plane passing through the center of the celestial sphere perpendicular to the plumb line is called true horizon plane. This plane, intersecting with the celestial sphere, forms a circle of a great circle, called the true horizon. The latter divides the celestial sphere into two parts: the above-horizon and sub-horizon.
A straight line passing through the center of the celestial sphere parallel to the earth's axis is called the axis of the world. The points of intersection of the axis of the world with the celestial sphere are called the poles of the world. One of the poles, corresponding to the poles of the Earth, is called the north celestial pole and is designated Pn, the other is called the south celestial pole Ps.
The plane QQ" passing through the center of the celestial sphere perpendicular to the axis of the world is called plane of the celestial equator. This plane, intersecting with the celestial sphere, forms a circle of a large circle - celestial equator, which divides the celestial sphere into northern and southern parts.
The great circle of the celestial sphere passing through the poles of the world, zenith and nadir, is called meridian of the observer PN nPsZ. The axis of the world divides the meridian of the observer into noon PN ZPs and midnight PN nPs parts.
The meridian of the observer intersects with the true horizon at two points: the north point N and the south point S. The straight line connecting the north and south points is called noon line.
If you look from the center of the sphere to point N, then the east point O st will be on the right, and the west point W will be on the left. Small circles of the celestial sphere aa", parallel planes true horizon is called almucantarates; small bb" parallel to the plane of the celestial equator, - celestial parallels.
Circles of the celestial sphere Zon passing through the zenith and nadir points are called verticals. The vertical passing through the points east and west is called the first vertical.
Circles of the celestial sphere PNoPs passing through the celestial poles are called declination circles.
The meridian of the observer is both a vertical and a circle of declination. It divides the celestial sphere into two parts - eastern and western.
The pole of the world, located above the horizon (below the horizon), is called the elevated (lowered) pole of the world. The name of the elevated pole of the world is always of the same name with the name of the latitude of the place.
The axis of the world with the plane of the true horizon makes an angle equal to geographical latitude places.
The position of the luminaries on the celestial sphere is determined using spherical coordinate systems. In nautical astronomy, horizontal and equatorial coordinate systems are used.
Celestial sphere- an abstract concept, an imaginary sphere of infinitely large radius, the center of which is the observer. At the same time, the center of the celestial sphere is, as it were, at the level of the observer's eyes (in other words, everything that you see above your head from horizon to horizon is this very sphere). However, for ease of perception, we can consider the center of the celestial sphere and the center of the Earth, there is no mistake in this. The positions of the stars, planets, the Sun and the Moon are applied to the sphere in the position in which they are visible in the sky at a certain point in time from a given point of the observer's location.
In other words, although observing the position of the luminaries in the celestial sphere, we, being in different places on the planet, will constantly see a slightly different picture, knowing the principles of the "work" of the celestial sphere, looking at the night sky, we can easily orient ourselves on the ground using a simple technique. Knowing the view overhead at point A, we compare it c with the view of the sky at point B, and by the deviations of familiar landmarks, we can understand exactly where we are now.
People have long thought whole line tools to make our task easier. If you navigate the "earthly" globe simply with the help of latitude and longitude, then a number of similar elements - points and lines, are also provided for the "heavenly" globe - the celestial sphere.
Celestial sphere and position of the observer. If the observer moves, then the whole sphere visible to him will move.
Elements of the celestial sphere
The celestial sphere has a number of characteristic points, lines and circles, let's consider the main elements of the celestial sphere.
Observer vertical
Observer vertical- a straight line passing through the center of the celestial sphere and coinciding with the direction of the plumb line at the point of the observer. Zenith- the point of intersection of the observer's vertical with the celestial sphere, located above the observer's head. Nadir- the point of intersection of the vertical of the observer with the celestial sphere, opposite to the zenith.
True horizon- a large circle on the celestial sphere, the plane of which is perpendicular to the vertical of the observer. The true horizon divides the celestial sphere into two parts: suprahorizontal hemisphere where the zenith is located, and subhorizontal hemisphere, in which the nadir is located.
Axis of the world (Earth axis)- a straight line around which the visible daily rotation of the celestial sphere occurs. The axis of the world is parallel to the axis of rotation of the Earth, and for an observer located at one of the poles of the Earth, it coincides with the axis of rotation of the Earth. The apparent daily rotation of the celestial sphere is a reflection of the actual daily rotation of the Earth around its axis. The poles of the world are the points of intersection of the axis of the world with the celestial sphere. The pole of the world, located in the constellation Ursa Minor, is called north pole world, and the opposite pole is called south pole.
A large circle on the celestial sphere, the plane of which is perpendicular to the axis of the world. The plane of the celestial equator divides the celestial sphere into northern hemisphere, in which the North Pole of the World is located, and southern hemisphere where the South Pole of the World is located.
Or the meridian of the observer - a large circle on the celestial sphere, passing through the poles of the world, zenith and nadir. It coincides with the plane earth meridian observer and divides the celestial sphere into eastern and western hemisphere.
Points north and south- points of intersection of the celestial meridian with the true horizon. The point closest to the North Pole of the world is called the north point of the true horizon C, and the point closest to the South Pole of the world is called the south point Yu. The points of east and west are the points of intersection of the celestial equator with the true horizon.
noon line- a straight line in the plane of the true horizon, connecting the points of north and south. This line is called noon because at noon, local true solar time, the shadow from the vertical pole coincides with this line, that is, with the true meridian of this point.
Points of intersection of the celestial meridian with the celestial equator. The point closest to the southern point of the horizon is called point south of the celestial equator, and the point closest to the northern point of the horizon is point north of the celestial equator.
Vertical luminaries
Vertical luminaries, or height circle, - a large circle on the celestial sphere, passing through the zenith, nadir and luminary. The first vertical is the vertical passing through the points of east and west.
Declension circle, or , - a large circle on the celestial sphere, passing through the poles of the world and the luminary.
A small circle on the celestial sphere, drawn through the luminary parallel to the plane of the celestial equator. The visible daily movement of the luminaries occurs along the daily parallels.
Almukantarat luminaries
Almukantarat luminaries- a small circle on the celestial sphere, drawn through the luminary parallel to the plane of the true horizon.
All the elements of the celestial sphere noted above are actively used to solve practical problems of orientation in space and determining the position of the stars. Depending on the purposes and conditions of measurement, two different systems are used. spherical celestial coordinates.
In one system, the luminary is oriented relative to the true horizon and is called this system, and in the other, relative to the celestial equator and is called.
In each of these systems, the position of the luminary on the celestial sphere is determined by two angular values, just as the position of points on the surface of the Earth is determined using latitude and longitude.
All points of the celestial sphere of five letters are listed below. A brief description is given for each of the definitions.
If you have something to add, then below is at your service a commenting form in which you can express your opinion or supplement the article.
North
One of the four conventionally accepted cardinal directions, which is opposite to the south. On the geographical map predominantly located at the top and is indicated by a capital letter C (international designation N - north).
A magnetized compass needle always points north. The etymology of this word comes from Old Russian language, in translation "cold", "cold wind". Also, the North (Far North) is called the area that lies in this direction. The Far North and the North Pole are part of the territory of Russia.
It should be noted that, as geographical feature, the North Pole does not exist. This is a certain point that marks the axis of the Earth. The British James and John Ross were the first to talk about the existence North Pole. But the debate about who nevertheless discovered it first is still going on. Due to the harsh climate (in winter - about - 40C, in summer about 0C) animal world very scarce. Polar bears, walruses, seals mainly live here. And because of eternal ice no vegetation at all.
West
One of four conditional accepted by man sides of the world. The west point lies at the intersection of the celestial equator and the horizon, midway between north and south and opposite east. On the geographical map, the west is indicated on the left by the letter З (international designation - W "west"). The word came to us from ancient times. Originally, the word west meant "sunset" because the Sun sets in the west ("sets" below the horizon), due to the rotation of the Earth around an imaginary axis from west to east. The West is also called the area lying in this direction.
Zenith
The etymology of this word is very complex. The word zenith is considered an error word, i.e. when borrowing words from other languages, a mistake is made in the word. So when borrowing the word zenith from Arabic, a typing error was made. AT Arabic word"zamt", which meant "the highest point of the sky", confused "m" with "in" and got the word "zanit", later it turned into "zenit". Zenith is an imaginary celestial point that is above the observer's head.
Simply put, the zenith is the direction that points "up" from a given point on the earth, a direction that is strictly opposite to the direction of gravity at that location. The angle between the horizon and the zenith is 90. The term zenith also refers to the highest point reached by a celestial body as it orbits. So the word zenith is often used to determine the position of the Sun. There is an expression "The sun is at its zenith", i.e. The sun has reached highest point above the horizon at that location.
Nadir
This word is borrowed from Arabic. A nadir is an imaginary celestial point at which the celestial sphere and a vertical line pointing down from the observation point intersect. This point is located on the other half of the celestial sphere, invisible to humans because of the globe. Nadir is opposite to the zenith point, i.e. under the feet of the observer, on the other side of the Earth. The angle between the nadir and the horizon is 90°. Simply put, the nadir is the direction opposite to the zenith, and therefore the direction that coincides with the direction of gravity.
Apex
This term has Latin roots. The exact meaning of the word apex is "apex" from the Latin "apex". Apex - a certain point that is located in the celestial sphere, moving towards it space objects in this moment. The opposite point is called the antiapex. Since all objects of the Universe are under the action of gravitational forces and do not move in a straight line, their apexes are constantly shifting.
More meanings of this word and English-Russian, Russian-English translations for the word "POINT OF THE SKY SPHERE" in dictionaries.
- DOT- f. point, place, spot, dot; point of view, point of view; mass point, discrete mass point; critical point, critical point; …
Russian-English Dictionary of the Mathematical Sciences - DOT—Point
- SPHERES— Spheres
Russian-American English Dictionary - DOT
- DOT- 1 point; (speck, icon) dot; dotted line dotted line; highest ~ mountain range highest point of mountain chain; broadcasting …
Russian-English Dictionary of General Subjects - DOT- 1) dot 2) point 3) punctum
New Russian-English Biological Dictionary - DOT—Point
Russian Learner's Dictionary - SPHERES— Orbs
Russian Learner's Dictionary - DOT- pinpoint
Russian Learner's Dictionary - SPHERES spheres
Russian Learner's Dictionary - DOT- 1. f. 1. (in different meanings) point; (speck) dot, spot point of intersection - point of intersection ...
Russian-English dictionary - DOT- 1. f. 1. (in different meanings) point; (speck) dot, spot point of intersection - point of intersection ...
Russian-English Smirnitsky abbreviations dictionary - DOT- The area at the intersection of imaginary lines of a rectangular grid, which is an elementary section of the image created by a computer on a screen or a printer on ...
Russian-English Edic - DOT— point, spot
Russian-English Dictionary of Mechanical Engineering and Automation of Production - DOT- I wives. 1) (in different meanings) point; (speck) dot, spot every point on the globe - every spot on ...
Russian-English short dictionary in general vocabulary - DOT- prick, dot, station geod., speck, sharpening, site, spot, (review, photography, etc.) view-point
Russian-English Dictionary of Construction and New Construction Technologies - DOT—Point
British Russian-English Dictionary - DOT— point
Russian-English Economic Dictionary - DOT- (blat.) underground "shop" selling drugs
English-Russian-English dictionary of slang, jargon, Russian names - DOT- 1 point; (speck, icon) dot; dotted line dotted line; highest ~ mountain range highest point of mountain chain; broadcasting ~ radio relay station; trading …
Russian-English Dictionary - QD - DOT— point
Russian-English Law Dictionary - DOT- see inner ~ ; starting ~ ; average ~
Russian-English Scientific and Technical Translator's Dictionary - DOT- well. point shift point on the graph - shift point point of intersection of the wheel axis of rotation with the road - pivot center - base point - top ...
Russian-English automobile dictionary - DOT- 1) dot 2) (decimal or at the end of a sentence) period 3) point
Russian-English dictionary terms and abbreviations on BT, the Internet and programming - DOT- see at the point; at a point on the earth; value at the same point; magnetic conjugate points; opposite point of Apex… …
Russian-English Dictionary of Space Idioms - DOT!— F enough! s.a. exactly
- DOT- I wives. 1) (in different meanings) point (speck) dot, spot every point on the globe - every spot on the globe ...
Big Russian-English Dictionary - SPHERES– orthocentre
Big Russian-English Dictionary - DOT- point spot;full stop
Russian-English Dictionary Socrates - ASTRONOMY
Russian Dictionary Colier - HOUSE- 1. noun; pl. -s 1) house; housing; building to build, put up a house ≈ build a house to redecorate, refurbish, ...
- HEAVENLY- SKY SPHERE Characteristic Alt-azimuth system Equatorial system Geographic system Basic circle Horizon Celestial equator Equator Poles Zenith and nadir North ...
Russian Dictionary Colier - HEAVENLY- When we observe the sky, all astronomical objects appear to be located on a domed surface, in the center of which the observer is located. This imaginary dome...
Russian Dictionary Colier - POLE- two points of intersection of the surface of the sphere with the axis of its rotation. On Earth, these poles are called North and South, and they are assigned ...
Russian Dictionary Colier - ASTRONOMY- ASTRONOMY AND ASTROPHYSICS The heyday of the Greek (Hellenistic) civilization at the time of the extinction of the Babylonian and Egyptian was marked by major changes in practical and theoretical ...
Russian Dictionary Colier - WORLD POWER- world power (religion) the power of this world (as opposed to heavenly)
Big English-Russian Dictionary - STAR CHAMBER
Big English-Russian Dictionary - STAR CHAMBER- 1) Star Chamber (hall in Westminster) 2) East. Star Chamber (in full - Court of Star Chamber; from the 15th century - ...
Big English-Russian Dictionary - SOCIAL WORKER- employee social sphere sphere worker social problems(mainly public institutions health care, social security, etc.; such workers visit lonely ...
Big English-Russian Dictionary - POINT- 1. n. 1) The freezing point of water is 32 degrees Fahrenheit. ≈ Freezing point of water - 32 degrees ...
Big English-Russian Dictionary - OUT OF- suggestion outside; over, above, beyond; outside Syn: outside, beyond, without indicates movement from within, from - he took a ...
Big English-Russian Dictionary - ORTHOCENTER- center of an inscribed circle, sphere (mathematics) orthocenter, center of an inscribed circle or sphere
Big English-Russian Dictionary - MERIDIAN- 1. n. 1) geogr. meridian 2) zenith a) the upper point of intersection of the plumb line with the celestial sphere Syn: zenith b) ...
Big English-Russian Dictionary - CELESTIAL- 1. adj. 1) heavenly; astronomical (about material objects, phenomena) celestial equator ≈ celestial mechanics ≈ mechanics celestial bodies …
Big English-Russian Dictionary - BEAT
Big English-Russian Dictionary - SPHERE- (in different values) sphere; (region also) realm celestial sphere astr. - celestial sphere sphere of influence watered. …
English-Russian-English Dictionary general vocabulary- Compilation of best dictionaries - MANNA- manna wait like manna from heaven (rd.) - thirst (for), await with impatience (d.) eat manna from heaven ...
English-Russian-English Dictionary of General Vocabulary - Collection of the best dictionaries - POINT- point.ogg 1. pɔınt n _I 1. 1> point (full) point - point (punctuation mark) interrogation exclamation point - ...
English-Russian-English Dictionary of General Vocabulary - Collection of the best dictionaries - OUT OF- phr prep 1. indicates 1> movement from the inside out of he took a handkerchief out of his pocket - he took out ...
English-Russian-English Dictionary of General Vocabulary - Collection of the best dictionaries - - 1) field of activity 2) sphere 3) ball. curve lies on sphere - the curve lies on the sphere develop sphere on plane - expand a spherical surface ...
- POINT- 1) engineering. score 2) division 3) sharpening 4) comma 5) size 6) place 7) topogr. cape 8) tip 9) point 10) sharp end 11) point 12) object 13) item 14) embroider 15) embroider 16) set ...
English-Russian Scientific and Technical Dictionary