When solving various problems of aviation astronomy, it is necessary to determine the position of the luminaries in the celestial sphere. For this, celestial coordinate systems are used. Depending on the purposes and conditions of measurement in aviation astronomy, two systems of spherical celestial coordinates are used. In one system, the luminary is oriented relative to true horizon and they call this system horizontal, and in the other - relative to the celestial equator and call it equatorial. 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.
Horizontal system of celestial coordinates.
The main plane in this celestial coordinate system is the plane of the true horizon, and the poles are the zenith and nadir. The position of the luminary in this coordinate system is determined by the azimuth and height of the luminary (Fig. 1.2)
The azimuth of the star A is the dihedral angle in the plane of the true horizon, enclosed between the plane of the celestial meridian and the plane of the star's vertical. Azimuth is measured from the northern direction of the celestial meridian in a clockwise direction from 0 to 360 °. Suns that are on the same vertical have the same azimuths.
The position of the luminary on the vertical is determined by another coordinate - height. The height of the luminary L is the angle between the plane of the true horizon and the direction to the luminary from the center of the celestial sphere. Height can also be measured by a vertical arc from the plane of the true horizon to the luminary's almucantar. Height is measured from 0 to ±90°.
Rice. 1.2. Horizontal celestial coordinate system
Rice. 1. 3. The position of the luminaries on the celestial sphere:
Rice. 1. 4. Equatorial system of celestial coordinates
Positive heights are counted towards the zenith, and negative heights are counted towards the nadir, i.e., the luminaries above the horizon have a positive height, and those below the horizon have a negative height. Instead of the height of the star, they sometimes use another coordinate - the zenith distance.
The zenith distance Z is the angle in the vertical plane between the vertical of the observer and the direction to the luminary from the center of the celestial sphere. The zenith distance is measured from the zenith point to the direction to the star from 0 to 180 °.
Between the height and zenith distance of the star there is the following relationship:
The luminaries located on the same almucantarate have the same heights and the same zenith distances.
The horizontal coordinates of the luminaries continuously and unevenly change due to the daily rotation of the Earth. They also change with a change in the place of the observer. However, horizontal coordinates are convenient in that they can be directly measured with the help of special instruments and it is easy to imagine the position of the luminary on the celestial sphere from them. Below are examples of a graphical representation of the position of the bodies on the celestial sphere according to given horizontal coordinates.
Example 1. Azimuth of the luminary height of the luminary.
Example 2. The azimuth of the luminary is the zenith distance of the luminary.
The position of the luminaries on the celestial sphere for these examples is shown in Fig. 1.3.
Equatorial system of celestial coordinates.
The main plane in this system of celestial coordinates is the plane of the celestial equator, and the poles are the poles of the world. The position of the luminary in this coordinate system is determined by the declination and hourly angle of the luminary (Fig. 1.4).
The declination of the luminary b is the angle enclosed between the plane of the celestial equator and the direction to the luminary from the center of the celestial sphere. The declination of the luminary is measured from 0 to ±90°. Positive declination is counted towards the North Pole of the world, and negative declination - towards the South. The declination of the Sun, Moon and planets is given in the Aviation Astronomical Yearbook for each hour of Greenwich Time (Appendix 5), and navigation stars - in the table of equatorial coordinates of stars at the beginning of each year (Appendix 2) due to its change for the year by only 1-2. Sometimes, instead of the declination of the luminary, another coordinate is used - the polar distance.
The polar distance P is the angle in the plane of the circle of declination, enclosed between the axis of the world and the direction to the luminary from the center of the celestial sphere. The polar distance is measured from the North Pole of the world to the South from 0 to 180 °. Between the polar distance and the declination of the star there is the following relationship:
Luminaries located on the same daily parallel have the same declinations and the same polar distances.
The declination, or polar distance, determines the position of the star on the declination circle.
The position of the circle of declination itself on the celestial sphere is determined by the hourly angle of the star.
The hourly angle of the star t is the dihedral angle in the plane of the celestial equator, enclosed between the plane of the celestial meridian and the plane of the declination circle of the star.
The hour angle is measured from south direction celestial meridian clockwise (to the west) to the circle of declination of the star from 0 to 360 °. It is important to know that the hour angle of the star is measured in the direction of the daily rotation of the celestial sphere.
When solving some problems, for convenience, the hour angles of the luminaries count from 0 to 180 ° to the west and east and, accordingly, designate them. In the Aviation Astronomical Yearbook, the western hour angles of the luminaries are given from 0 to 360 °, and in the calculation tables for the Sun, Moon and planets - from 0 to 180 °.
Rice. 1.5. The position of the luminaries
on the celestial sphere: a - for b - for
Rice. 1. 6. Relationship between the height of the celestial pole and geographic latitude
In the practice of aviation astronomy, the relationship between the hourly angle of the star and the longitude of the observer's place is of great importance. It was indicated above that the hourly angle of the star is usually counted to the west of the celestial meridian. Since the plane of the celestial meridian coincides with the geographic meridian of the observer, then at the same time the hour angles of the same luminary for observers located on different meridians will be different.
Obviously, at the same moment of time, the difference in the local hourly angles of the star is equal to the difference in the longitudes of the observers. If taken in this ratio then . Taking , we get . As can be seen from the resulting formula, the local hourly angle of the star differs from Greenwich Mean Time by the value of the longitude of the observer. In practice, instead of the hour angle, the luminaries often use another coordinate - the right ascension of the luminary.
The right ascension of the luminary a is the angle enclosed between the plane of the circle of declination of the vernal equinox (the initial circle of declination) and the plane of the circle of declination of the luminary.
The point of the vernal equinox is the point of intersection of the plane of the celestial equator by the center of the Sun (March 21) during its apparent annual movement in the celestial sphere. This point is usually denoted by the symbol of the constellation Aries, in which it was located in the era of the birth of astronomy.
The right ascension of the star is measured in the plane of the celestial equator from the point of the vernal equinox counterclockwise (to the east) to the circle of declination of the star from 0 to 360 °. The right ascension of the star and its hourly angle can be measured not only by the angle, but also by the puff of the celestial equator, and the declination and polar distance of the star by the arc of the declination circle.
In aviation astronomy, the equatorial celestial coordinate system is divided into two systems.
In the first equatorial system, the position of the luminary on the celestial sphere is determined by the declination and hourly angle, and in the second, by the right ascension and declination of the luminary. The first equatorial system is taken as the basis for the development and creation of astronomical compasses, as well as for compiling calculation tables. The second equatorial system is used to compile star charts and tables of equatorial coordinates of stars.
The equatorial celestial coordinate system is more practical than the horizontal one. It is of great practical importance in aviation astronomy. Associated with this system is the measurement of time and the determination of the position of an aircraft, i.e., the solution of the main problems of practical aviation astronomy.
Its main advantage is that the equatorial coordinates of the luminaries do not depend on the position of the observer on earth's surface, except for the local hour angle. The hourly angle of the star depends not only on the longitude of the observer's place, but also on the time of observation. It continuously changes in proportion to time, and this makes it possible to take into account in astrocompasses with the help of a clock mechanism its change due to the rotation of the Earth.
The declination and right ascension of the luminaries, as will be discussed in more detail later, also change with time, but much more slowly than the horizontal coordinates change. Their change occurs due to the fact that the celestial equator and the vernal equinox continuously change their position in space due to the precession of the Earth's axis of rotation. Below are examples of a graphic representation of the position of the luminaries on the celestial sphere according to the given equatorial coordinates.
Example 1. Western hourly angle of the star declination of the star.
Example 2. Right ascension of the star; the declination of the star is 60°.
The position of the luminaries on the celestial sphere for these examples is shown in Fig. 1.5.
DECLINE OF THE LIGHT
Its angular distance from the celestial equator. To the north of the equator is considered positive, to the south is considered negative. Denoted in Greek. letter (see Spherical coordinates).
Brockhaus and Efron. Encyclopedia of Brockhaus and Efron. 2012
See also interpretations, synonyms, meanings of the word and what is the DECLINE OF THE LIGHT in Russian in dictionaries, encyclopedias and reference books:
- DECLINE OF THE LIGHT
its angular distance from the celestial equator. To the north of the equator is considered positive, to the south is considered negative. Denoted in Greek. letter (see Spherical ... - DECLINE in the Big encyclopedic dictionary:
- LIGHTS in the Encyclopedic Dictionary of Brockhaus and Euphron:
see Stars, Planets and... - DECLINE in the Modern Encyclopedic Dictionary:
- DECLINE in the Encyclopedic Dictionary:
change in the name or nominal forms of the verb (for example, participles) in cases (in the singular and in the plural) a type of such change that has ... - DECLINE in the Encyclopedic Dictionary:
, -i, cf. 1. see ^ incline and incline, -sya. 2. In grammar: a class of nouns with the same forms of inflection; … - DECLINE
MAGNETIC DECLINE, angle between geogr. and magn. meridians at a given point on the earth's surface. Cm. is considered positive if end of magnet. … - DECLINE in the Big Russian Encyclopedic Dictionary:
declension (denoted by d), one of the eq. coordinates; the arc of the circle of declinations from the celestial equator to the luminary; counted on both sides of... - DECLINE in the Big Russian Encyclopedic Dictionary:
declension, name change by cases and numbers (see Inflection). A type of word change in cases and numbers, representing a special paradigm ... - LIGHTS
? see Stars, Planets and... - DECLINE in the Full accentuated paradigm according to Zaliznyak:
declension, declension, declension, declension, declension, declension, declension, declension, declension, declension, declension, ... - DECLINE in the Linguistic Encyclopedic Dictionary:
- 1) nominal inflection. In this sense, S. is opposed to conjugation, i.e., verbal inflection. S.'s rules constitute a necessary component of morphological. … - DECLINE in the Dictionary of Linguistic Terms:
1) Changing nouns by cases (for most names and numbers), and for adjectives and other agreed words also by ... - DECLINE in the dictionary of Synonyms of the Russian language:
declination, change, coordinate, bending, bending, tilt, inclination, lowering, lowering, prompting, worship, radio inclination, persuasion, persuasion, ... - DECLINE in the New explanatory and derivational dictionary of the Russian language Efremova:
1. cf. 1) The process of action by value. verb: incline (1 *), incline. 2) Deviation, evasion somewhere. 2. cf. 1) Change of names, ... - DECLINE in the Complete Spelling Dictionary of the Russian Language:
declension, ... - DECLINE in the Spelling Dictionary:
inclination, ... - DECLINE in the Dictionary of the Russian Language Ozhegov:
In grammar: a class of nouns with the same forms of inflection Nouns of the first, second, third declension. declination<= склонить и склонять 1, … - DECLINE in the Modern Explanatory Dictionary, TSB:
1) name change by cases and numbers (see Inflection). 2) Type of word change by cases and numbers, representing a special paradigm (1st ... - DECLINE in the Explanatory Dictionary of the Russian Language Ushakov:
declension, cf. 1. Action on verb. incline - incline (book). He expressed his agreement with a slight declension. heads. Declining someone. on someone's side. 2. Angle, ... - DECLINE in the Explanatory Dictionary of Efremova:
declension 1. cf. 1) The process of action by value. verb: incline (1 *), incline. 2) Deviation, evasion somewhere. 2. cf. 1) Change... - DECLINE in the New Dictionary of the Russian Language Efremova:
- DECLINE in the Big Modern Explanatory Dictionary of the Russian Language:
I cf. 1. the process of action according to Ch. incline I, incline 2. Deviation, evasion somewhere. II cf. 1. Change of names, pronouns… - RISE OF THE HEAVENLY LIGHT
celestial body, an astronomical phenomenon caused by the daily rotation of the Earth around its axis; the moment the luminary crosses the horizon when it passes into the visible, ... - VISIBLE DIAMETER OF THE LIGHT in the Great Soviet Encyclopedia, TSB:
the diameter of the luminary, the angular diameter of the luminary, the angle at which the linear diameter of the luminary is visible. Depends on the linear diameter and distance to the star. … - PRACTICAL ASTRONOMY in the Encyclopedic Dictionary of Brockhaus and Euphron:
teaches the most expedient arrangement, production and processing of observations with astronomical instruments necessary for solving one or another problem of astronomy. An essential part… - SUNRISE in the Encyclopedic Dictionary of Brockhaus and Euphron:
the appearance of a star above the horizon (see this word) of a given place; the disappearance of the luminary from the horizon is called sunset. Due to refraction (see this word) ... - PRACTICAL ASTRONOMY in the Encyclopedia of Brockhaus and Efron:
? teaches the most expedient arrangement, production and processing of observations with astronomical instruments necessary for solving one or another problem of astronomy. Essential… - SUNRISE in the Encyclopedia of Brockhaus and Efron:
? the appearance of a star above the horizon (see this word) of a given place; the disappearance of the luminary from the horizon is called sunset. Due to refraction (see this ... - GENERAL 1 in the Orthodox Encyclopedia Tree:
Open Orthodox Encyclopedia "TREE". Bible. Old Testament. Being. Chapter 1 Chapters: 1 2 3 4 5 6 ... - SPHERICAL ASTRONOMY in the Great Soviet Encyclopedia, TSB:
astronomy, a section of astrometry that develops mathematical methods for solving problems related to the study of the apparent location and movement of bodies (stars, the Sun, the Moon, planets, ... - REFRACTION (LIGHT IN THE ATMOSPHERE) in the Great Soviet Encyclopedia, TSB:
light in the atmosphere [late lat. refractio - refraction, from lat. refractus - refracted (refringo - I break, refract)], an atmospheric-optical phenomenon caused by refraction ... - PRACTICAL ASTRONOMY in the Great Soviet Encyclopedia, TSB:
astronomy, a branch of astrometry devoted to the doctrine of astronomical instruments and methods for determining time, geographical coordinates and azimuths from astronomical observations ... - PLANETARY ABERRATION in the Great Soviet Encyclopedia, TSB:
aberration, aberration of light coming from a planet, comet or other celestial body - a member of the solar system, due to the relative movement of this ... - PARALLAX (IN ASTRONOMY) in the Great Soviet Encyclopedia, TSB:
(parallactic shift) in astronomy, the apparent movement of the luminaries on the celestial sphere, due to the movement of the observer in space due to the rotation of the Earth (daily P.), ... - SKY COORDINATES in the Great Soviet Encyclopedia, TSB:
coordinates, numbers, with the help of which they determine the position of the luminaries and auxiliary points on the celestial sphere. In astronomy, various systems are used ... - CELESTIAL SPHERE in the Great Soviet Encyclopedia, TSB:
sphere, an imaginary auxiliary sphere of arbitrary radius, onto which heavenly bodies are projected; serves to solve various astrometric problems. Picture of … - NAVIGATION ASTRONOMY in the Great Soviet Encyclopedia, TSB:
astronomy, a section of practical astronomy that satisfies the needs of navigation. M.'s subject and. is the development of methods for determining by celestial bodies and navigation ... - GEODETIC ASTRONOMY in the Great Soviet Encyclopedia, TSB:
astronomy, the branch of practical astronomy most closely associated with geodesy and cartography; studies the theory and methods for determining the latitude j ... - ASTRONOMIC COMPASS in the Great Soviet Encyclopedia, TSB:
compass, an onboard navigational optical instrument for determining the true or orthodromic course (see Orthodromia) of an aircraft, surface or submarine ship ... - LIGHT ABERRATION in the Great Soviet Encyclopedia, TSB:
light in astronomy, a change in the direction of a light beam coming from a heavenly body, due to the finiteness of the speed of light and the movement of the observer relative to the star. … - JAKOBSTAB in the Encyclopedic Dictionary of Brockhaus and Euphron.
- ECLIPTIC in the Encyclopedic Dictionary of Brockhaus and Euphron:
a large circle of the celestial sphere, along which the apparent annual movement of the sun takes place; otherwise - the line of intersection of the celestial sphere with a plane parallel to ... - GONITIONAL ASTRONOMIC INSTRUMENTS in the Encyclopedic Dictionary of Brockhaus and Euphron:
Most practical tasks astronomy is reduced to measuring the apparent angular distances between the luminaries on the celestial sphere, or to determining those angles ...
The position of celestial bodies on the celestial sphere is uniquely determined by two spherical coordinates. The spherical coordinates of a point are arcs of the great circles of the sphere expressed in degrees or hours. A well-known example of such spherical coordinates are the coordinates of a point on the surface of the Earth - latitude and longitude. There are several systems of astronomical coordinates. These systems differ from each other in the choice of the main plane and the origin.
3.1. Horizontal coordinate system
The main plane is the plane of the true horizon, and the reference point is the south point S. The coordinates are the height and azimuth (Fig. 5).
Height shining above the horizon h, is the angular distance from the true horizon, measured along the star's vertical (analogous to latitude). The height of the luminary can vary from -90 o up to 90 o. A negative height means that the luminary is below the horizon. Example: zenith height is 90 o .
Instead of the height of the luminary, the first horizontal coordinate is often used zenith distance z- the angular distance of the luminary from the zenith, measured along the vertical of the luminary. There is a simple relationship between the zenithal distance and the height of the star
The zenith distance can vary from 0 o up to 180 o, and luminaries with a zenith distance greater than 90 o lie below the horizon and are unobservable.
The second horizontal coordinate is azimuth A- this is the angular distance from the south point S to the intersection of the star's vertical with the horizon, counted clockwise along the horizon. Azimuth can take values from 0 o up to 360 o and bears the name astronomical azimuth, Unlike geodetic azimuth, counted from the north point N clockwise.
3.2. First equatorial coordinate system
The main plane is the plane of the celestial equator, the reference point is point Q. The coordinates are the declination and the hour angle (Fig. 6).
declination of the luminary,- this is the angular distance from the celestial equator to the luminary, measured in a circle of declination. The declination ranges from -90 o up to 90 o, and the luminaries with 0 are located north of the equator, and with 0 - south of it. Less commonly used instead of declension polar distance, p, is the angular distance from the luminary to the pole.
Hourly angle, t, is the arc of the celestial equator between the celestial meridian and the declination circle of the luminary. Counted from the Q point clockwise. Changes from 0 o up to 360 o in degrees or from 0 h up to 24 h in hours (360 o corresponds 24 h , 1 h - 15 o , 1 m - 15", 1 s - 15").
The coordinates of stars in the horizontal and first equatorial coordinate systems change due to the daily rotation of the Earth, since in them the reference point is tied to the rotating Earth (south point S and point Q lie on the celestial meridian). This means that in order for the coordinates of the stars not to change due to the daily rotation, it is necessary to choose a reference point that is fixed relative to the stars and participates in the daily rotation. The vernal equinox was chosen as such a reference point, and the coordinate system in which the stars do not change their coordinates due to daily rotation is called the second equatorial coordinate system.
3.3. Second equatorial coordinate system
The great circle of the celestial sphere, along which the center of the Sun seems to move during the year due to the annual revolution of the Earth around the Sun, is called ecliptic. The ecliptic is tilted at an angle to the equator. The points of intersection of the ecliptic with the equator are called the equinoxes. The point at which the Sun passes from the southern part of the celestial sphere to the northern one is called vernal equinox point, and the opposite point of the autumnal equinox .
In the second equatorial coordinate system, the main plane, as in the first one, is the plane of the celestial equator, and the reference point is the vernal equinox (Fig. 7). The first coordinate is also declination. second coordinate, right ascension, is the arc of the celestial equator from the vernal equinox to the circle of declination of the star, counted counterclockwise. Like the hour angle, right ascension is measured in hours.
Tasks
5. Find the stars with coordinates for the epoch 1950.0 in the Bechvarzh Atlas (1962):
| 3 h 22 m | 8 o 51" | 7 h 25 m | 8 o 24" |
| 9 h 43 m | 24 o 00" | 18 h 04 m | 9 o 33" |
| 9 h 28 m | 63 o 17" | 14 h 43 m | 27 o 17" |
| 15 h 14 m | -9 o 12" | 6 h 41 m | 25 o 11" |
6. Find the coordinates for the 1950.0 epoch of the following stars from the same atlas: Vega (), Polar (), Gemma (), Betelgeuse (), Sirius (), Altair (), Deneb (), Capella (), Arcturus (), Spica ( ).
1 Basic provisions of the celestial sphere
To determine the apparent position of celestial bodies and study their movement in astronomy, the concept is introduced celestial sphere. A sphere has arbitrary dimensions and an arbitrary center. To its center at a point O an observer is placed, and the rotation of the sphere repeats the rotation of the firmament. Straight ZOZ′ stands for plumb line for the observer, wherever he is. Upper point above the observer's head Z called Zenith, and its opposite point Z'- called Nadir. big circle SWNE perpendicular plumb line called true horizon or mathematical horizon. math horizon divides the sphere into two halves , visible and invisible for the observer. Line RR'- called axis of the world, around this axis there is a rotation celestial sphere. Plane ЕQWQ′ perpendicular to axes of the world called celestial equator. He divides celestial sphere into two hemispheres northern and southern. Great circle of the celestial sphere PZQSP′Z′Q′N called celestial meridian. The celestial meridian divides the celestial sphere into East and Western hemisphere. Line NOS called noon line.
The position of the main elements of the celestial sphere relative to each other depends on the geographical latitude observer's position. at an angle to the plane of the mathematical horizon is the axis of the worldRR′. The positions of the luminaries in the sky are determined in relation to the main planes and the lines and points associated with them. celestial sphere and is expressed quantitatively in two quantities ( central corners or arcs of great circles) which are called celestial coordinates.
2 Horizontal coordinate system
Main plane horizontal system coordinates is mathematical horizonNWSE, and the report is from Z zenith and from one of the points of the mathematical horizon. One coordinate is zenith distancez( Zenith distance to south zv = φ - δ; to north zн = 180 - φ - δ) or the height of the sun above the horizon h. Height h luminaries M called the height of the vertical circle mM from mathematical horizon before luminaries, or center corner mOM between plane mathematical horizon and direction to luminary M. Heights are counted from 0 to 90 k zenith and from 0 to -90 Nadir. The zenith distance of the luminary is called the arc of the vertical circle ZM from light to zenith. z + h = 90 (1). The position of the vertical circle itself is determined by the coordinate arc - azimuth A. Azimuth A called an arc mathematical horizon sm from the point southS to a vertical circle passing through the luminary. Azimuths counted in the direction of rotation celestial sphere, i.e. west of the south point, ranging from 0 to 360. The coordinate system is used to directly determine the apparent positions of the luminaries using goniometric tools.
3 First equatorial coordinate system
Countdown start - celestial equator pointQ. One coordinate is declination. declination called an arc mm hour circle PMmP′ from the celestial equator to the luminary. They are counted from 0 to +90 to the north pole and from 0 to -90 to the south. p+=90. The position of the hour circle is determined hour anglet. hour angle luminaries M called the arc of heaven equatorQm from the top Q celestial equator to hour circle PMmP′, passing through the light. Hourly angles are measured in the direction of the daily rotation of the celestial sphere, to the west of Q in the range from 0 to 360 or from 0 to 24 hours. The coordinate system is used in practical astronomy to determine the exact time and daily rotation of the sky. Determines the daily movement of the Sun, Moon and other luminaries.
4 Second equatorial coordinate system
One coordinate is declination, another right ascensionα . direct ascent α luminaries M called the arc of the celestial equator ♈ m from the point spring equinox♈ to the hour circle passing through the luminary. It is counted in the direction opposite to the daily rotation in the range from 0 to 360 or from 0 to 24 hours. The system is used for determining star coordinates and compiling catalogs. Determines the annual movement of the Sun and other luminaries.
5 The height of the celestial pole above the horizon, the height of the star in the meridian
The height of the celestial pole above the horizon is always equal to the astronomical latitude of the observer's place:
- If the declination of the luminary less than latitude, then it culminates south of the zenith at z = φ - δ or on top h = 90 - φ + δ
- If the declination of the luminary equal to geographic latitude, then it culminates at the zenith and z = 0 , a h = + 90
- If the declination of the luminary more geographic latitude, then it culminates north of the zenith at z = c - φ or on top h = 90 + φ - c
6 Conditions for Sunrise and Sunset
non-setting luminaries.
the culmination of the luminaries.
top climax, if lower - lower climax.
For an observer at the poles there will only be non-setting luminaries.
The phenomenon of the luminary crossing the celestial meridian is called the culmination of the luminaries.
If the luminary crosses the upper part of the meridian, top climax, if lower - lower climax.
DECLINE OF THE LIGHT
DECLINE OF THE LIGHT
(Declination) - the arc of the meridian of the luminary from the equator to the place of the luminary. Denoted by the Greek letter δ (delta). If the luminary is in the northern hemisphere, then its S. is called nordic, or northern; if in the south, then south, or southern. If S. S. is of the same name with latitude, then it is considered positive and has a plus sign, but if S. S. is opposite with latitude, then it is negative and has a minus sign.
Samoilov K.I. Marine dictionary. - M.-L.: State Naval Publishing House of the NKVMF of the USSR, 1941
See what the "DECTION OF THE LIGHT" is in other dictionaries:
Its angular distance from the celestial equator. To the north of the equator is considered positive, to the south is considered negative. Denoted in Greek. letter (see Spherical coordinates) … Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron
declination of the luminary- astron. The angle between the direction to the luminary and the plane of the equator ... Dictionary of many expressions
declension, declension, cf. 1. Action according to Ch. incline incline (book). He expressed his agreement with a slight bow of his head. Swaying someone to one side. 2. The angle formed by the magnetic needle of the compass and the direction of the geographic ... ... Explanatory Dictionary of Ushakov
declination- I; cf. 1) to incline incline and incline incline. Greet someone. head bow. Engage in declining someone. on whose l., his side. 2) a) grams. Changing the name by cases and numbers ... Dictionary of many expressions
declination of the heavenly body- The angle between the direction to the star and the plane of the true horizon (one of the coordinates in the horizontal system of celestial coordinates, measured in degrees from the observer's plane: north - positive declination, south - negative ... ... Geography Dictionary
- (designated?) one of the equatorial coordinates; the arc of the circle of declinations from the celestial equator to the luminary; counted in both directions from the equator (from 0 to? 90 .; in the northern hemisphere of the celestial sphere, the declination is positive) ... Big Encyclopedic Dictionary
DECLINE (denoted by d), one of the equatorial coordinates; the arc of the circle of declinations from the celestial equator to the luminary; counted in both directions from the equator (from 0 to ± 90 °; in the Northern Hemisphere of the celestial sphere, the declination is positive) ... encyclopedic Dictionary
The arc of the celestial meridian from the equator to some point on the celestial sphere (for example, to the place of the luminary). It is counted from 0 to 90 ° north (has a + sign and is denoted by the letter N and to the south (has signs is denoted by the letter S. It is one of ... ... Marine Dictionary
I; cf. 1. to Decline Decline and Decline Decline. Greet someone. head bow. Engage in declining someone. on whose l., his side. 2. Gram. Changing the name by cases and numbers (nouns, adjectives, ... ... encyclopedic Dictionary
This term has other meanings, see Declension. Equatorial coordinate system Declination (δ) in astronomy is one of two coordinates ... Wikipedia