As a result of the motion of the Earth in its orbit, it seems to an observer on Earth that the Sun is constantly moving around the celestial sphere relative to the fixed stars.
True, it is not possible to observe the movement of the Sun relative to the stars, because. The stars are not visible during the daytime. We list some convincing facts about the movement of the Sun relative to the stars
1. At different times of the year, different stars are visible at midnight.
2. The meridional height of the Sun changes throughout the year.
3. The azimuths of sunrise and sunset also change, as well as the length of day and night.
Ecliptic(from Latin ecliptica - eclipse), a large circle of the celestial sphere, along which the visible annual movement of the Sun occurs.
A modern, more accurate definition of the ecliptic is a section of the celestial sphere by the plane of the orbit of the barycenter of the Earth-Moon system.
The Earth, moving along its orbit, maintains the same position of its axis of rotation in world space.
The angle of inclination of the Earth's axis of rotation with the plane of the Earth's orbit is 66°33", therefore, the angle between the plane of the Earth's orbit and the plane of the Earth's equator is 23°26".
The ecliptic is the projection of the plane of the earth's orbit onto the celestial sphere.
Because the plane of the celestial equator is a continuation of the earth's equator, and the plane of the ecliptic is the plane of the Earth's orbit, then the plane of the ecliptic makes an angle with the plane of the celestial equator = 23 ° 27 ".
Due to the fact that the Moon's orbit is inclined relative to the ecliptic and due to the rotation of the Earth around the barycenter of the Moon-Earth system, plus also due to the perturbations of the Earth's orbit from other planets, the true Sun is not always exactly on the ecliptic, but can deviate by several seconds of arc. We can say that the path of the "average Sun" passes along the ecliptic.
The plane of the ecliptic is inclined to the plane of the celestial equator at an angle: ε = 23°26′21.448″ - 46.815″ t - 0.0059″ t² + 0.00181″ t³, where t is the number of Julian centuries that have elapsed since the beginning of 2000. This formula is valid for the coming centuries. Over longer periods of time, the obliquity of the ecliptic to the equator fluctuates about the mean with a period of approximately 40,000 years.
In addition, the inclination of the ecliptic to the equator is subject to short-period fluctuations with a period of 18.6 years and an amplitude of 18.42″, as well as smaller ones.
Unlike the plane of the celestial equator, which changes its inclination relatively quickly, the plane of the ecliptic is more stable relative to distant stars and quasars, although it is also subject to slight changes due to perturbations from the planets of the solar system.
The name "ecliptic" is associated with the fact known since ancient times that solar and lunar eclipses occur only when the Moon is near the points of intersection of its orbit with the ecliptic. These points on the celestial sphere are called the lunar nodes, their cycle of revolution along the ecliptic, equal to about 18 years, is called the Saros, or Draconic period.
The ecliptic passes through the zodiac constellations and the constellation Ophiuchus.
The plane of the ecliptic serves as the main plane in the ecliptic celestial coordinate system.
Also, the ecliptic is of fundamental importance in astrology, most schools of this occult discipline include the interpretation of the positions of the heavenly bodies in the signs of the zodiac, that is, they consider their positions precisely on the ecliptic.
Also important for most schools of astrology, the angular distances between the luminaries in the overwhelming majority of cases are determined in astrology, taking into account only their ecliptic longitude, and in this sense, the aspects are “resonances” not so much between the real positions of the luminaries on the celestial sphere, but actually between their ecliptic projections, that is, between the points of the ecliptic - their ecliptic longitudes.
The two points where the ecliptic intersects the celestial equator are called the equinoxes.
At the point of the vernal equinox, the Sun in its annual movement passes from the southern hemisphere of the celestial sphere to the northern one; at the point of the autumnal equinox - from the northern hemisphere to the southern. The two points on the ecliptic that are 90° away from the equinoxes and thus the furthest from the celestial equator are called the solstice points.
The summer solstice is in the northern hemisphere, the winter solstice is in the southern hemisphere.
These four points are designated by the symbols of the zodiac corresponding to the constellations in which they were located at the time of Hipparchus (as a result of the prelude of the equinoxes, these points have shifted and are now in other constellations): the spring equinox - the sign of Aries (♈), the autumn equinox - the sign of Libra (♎), the winter solstice is the sign of Capricorn (♑), the summer solstice is the sign of Cancer (♋).
The axis of the ecliptic is the diameter of the celestial sphere, perpendicular to the plane of the ecliptic. The axis of the ecliptic intersects with the surface of the celestial sphere at two points - the north ecliptic pole, which lies in the northern hemisphere, and the south ecliptic pole, which lies in the southern hemisphere. The north ecliptic pole has equatorial coordinates R.A. = 18h00m, Dec = +66°33", and is in the constellation Draco.
The circle of ecliptic latitude, or simply the circle of latitude, is a large semicircle of the celestial sphere passing through the poles of the ecliptic.
The Aries point is the point on the celestial sphere at which the Sun, in its apparent annual movement, changes its declination from south to north. The Sun comes to this point every year on March 21st - on the day of the spring equinox.
The point of Aries sets the reference point for one more coordinate - for right ascension.
Right ascension is the arc of the celestial equator from the point of Aries to the meridian of the star, in the direction of reverse western hourly angles (or if viewed from the north pole, then counterclockwise). It is in this direction that the Sun and Moon move in the celestial sphere and, consequently, the right ascension of these luminaries increases.
Tropical year is the period of time between two successive passages of the center of the Sun through the point of Aries. Its duration is 365.2422 days. This period is the basis of the calendar year. Refinement of the value of the tropical year has left its mark on the history of astronomy in the form of the Egyptian year, Julian and Gregorian styles.
For approximate calculations, it is necessary to know the daily changes in the coordinates of the Sun. The right ascension of the Sun varies almost uniformly throughout the year. The daily rate of change of the right ascension of the Sun is 360°/365.2422 1°/day.
The Sun's declination varies unevenly throughout the year.
0.4 ° / day for 1 month before and 1 month after the equinoxes;
0.1 ° / day for 1 month before and 1 month after the solstices;
0.3 °/day for the remaining 4 intermediate months.
In popular science articles on the topics of space and astronomy, one can often come across the not entirely clear term "ecliptic". This word is often used by astrologers besides scientists. It is used to indicate the location of space objects distant from the solar system, to describe the orbits of celestial bodies in the system itself. So what is the "ecliptic"?
What's with the zodiac
The ancient priests, who were still observing the heavenly bodies, noticed one feature of the behavior of the Sun. It appears to move relative to the stars. Tracking its movement across the sky, observers noticed that exactly one year later, the Sun always returns to its starting point. Moreover, the "route" of movement from year to year is always the same. It is called the "ecliptic". This is the line along which our main luminary moves across the sky during the calendar year.
The stellar regions through which the path of the shining Helios ran in his golden chariot drawn by golden horses (this is how the ancient Greeks imagined our native star) were not left without attention.
The circle of 12 constellations along which the Sun moves was called the zodiac, and these constellations themselves are commonly called zodiac.
If according to the horoscope you are, say, Leo, then do not look in the sky at night in July, the month in which you were born. The Sun is in your constellation during this period, which means that you can see it only if you are lucky to catch a total solar eclipse.
ecliptic line
If you look at the starry sky during the day (and this can be done not only during a total solar eclipse, but also with the help of a conventional telescope), we will see that the sun is located at a certain point in one of the zodiac constellations. For example, in November this constellation will most likely be Scorpio, and in August - Leo. The next day, the position of the Sun will shift slightly to the left, and this will happen every day. And a month later (November 22), the luminary will finally reach the border of the constellation Scorpio and move to the territory of Sagittarius.
In August, it is clearly seen in the figure, the Sun will be in the boundaries of Leo. Etc. If every day we mark the position of the Sun on a star map, then in a year we will have a map with a closed ellipse drawn on it. So this very line is called the ecliptic.
When to watch
But to observe your constellations under which a person is born) will turn out in the month opposite to the date of birth. After all, the ecliptic is the route of the Sun, therefore, if a person is born in August under the sign of Leo, then this constellation is high above the horizon at noon, that is, when the sunlight does not allow him to be seen.
But in February, Leo will decorate the midnight sky. On a moonless, cloudless night, it is perfectly “read” against the background of other stars. Those born under the sign of, say, Scorpio are not so lucky. The constellation is best seen in May. But to consider it, you need to stock up on patience and luck. It is better to go out of town, to an area without high mountains, trees and buildings. Only then will the observer be able to see the outline of Scorpio with its ruby Antares (alpha Scorpio, a bright blood-red star belonging to the class of red giants, having a diameter comparable to the size of the orbit of our Mars).
Why is the expression "plane of the ecliptic" used?
In addition to describing the stellar path of the annual motion of the Sun, the ecliptic is often considered as a plane. The expression "plane of the ecliptic" can often be heard when describing the position in space of various space objects and their orbits. Let's figure out what it is.
If we return in the scheme of motion of our planet around the parent star and the lines that can be drawn from the Earth to the Sun at different points in time, put together, it turns out that they all lie in the same plane - the ecliptic. This is a kind of imaginary disk, on the sides of which all 12 described constellations are located. If a perpendicular is drawn from the center of the disk, then in the northern hemisphere it will rest against a point on the celestial sphere with coordinates:
- declination +66.64°;
- right ascension - 18 h. 00 min.
And this point is located not far from both "bears" in the constellation Draco.
The axis of rotation of the Earth, as we know, is inclined to the axis of the ecliptic (at 23.44 °), due to which the planet has a change of seasons.
And our "neighbors"
Here is a summary of what the ecliptic is. In astronomy, researchers are also interested in how other bodies in the solar system move. As calculations and observations show, all the main planets revolve around the star in almost the same plane.
Most of all, the closest planet to the star is Mercury, which stands out from the overall slender picture, the angle between its plane of rotation and the ecliptic is as much as 7 °.
Of the planets of the outer ring, the orbit of Saturn has the largest angle of inclination (about 2.5 °), but given its enormous distance from the Sun - ten times farther than the Earth, this is excusable for the solar giant.
But the orbits of smaller cosmic bodies: asteroids, dwarf planets and comets deviate from the plane of the ecliptic much more strongly. So, for example, Pluto's twin, Eris, has an extremely elongated orbit.
Approaching the Sun at a minimum distance, it flies closer to the star than Pluto, at 39 AU. e. (a. e. - an astronomical unit equal to the distance from the Earth to the Sun - 150 million kilometers), in order to then again retire into the Kuiper belt. Its maximum removal is almost 100 AU. e. So its plane of rotation is inclined to the ecliptic by almost 45 °.
- Moon .
Description
The name "ecliptic" is associated with the fact known since ancient times that solar and lunar eclipses occur only when the Moon is near the points of intersection of its orbit with the ecliptic. These points on the celestial sphere are called lunar nodes, their period of revolution along the ecliptic, equal to about 18 years, is called saros, or draconic period.
The plane of the ecliptic serves as the base plane in the ecliptic celestial coordinate system.
The angles of inclination of the orbits of the planets of the solar system to the plane of the ecliptic
| Planet | Tilt to the ecliptic |
|---|---|
| Mercury | 7.01° |
| Venus | 3.39° |
| Earth | 0° |
| Mars | 1.85° |
| Jupiter | 1.31° |
| Saturn | 2.49° |
| Uranus | 0.77° |
| Neptune | 1.77° |
Ecliptic in literature
In Stanislav Lem's "Pirx's Tale" (from the series "Stories about the pilot Pirx") the ecliptic plane is a zone forbidden for spaceships, but the pilot Pirks, due to a number of circumstances, has to fly in it. That is why he manages to see a long-dead alien ship brought into the plane of the ecliptic by an off-system meteorite swarm.
see also
- Invariant plane ( English)
Write a review on the article "Ecliptic"
Notes
Literature
- Panchenko D. Who found the Zodiac? // Antike Naturwissenschaft und ihre Rezeption. - 1998. - Vol. 9. - P. 33-44.
- Brack-Bernsen L.// Centaurus. - 2003. - Vol. 45.-P. 16–31.
Links
- // Encyclopedic Dictionary of Brockhaus and Efron: in 86 volumes (82 volumes and 4 additional). - St. Petersburg. , 1890-1907.
- Ecliptic- article from the Great Soviet Encyclopedia.
|
||||||||||||||||||||||||||||||
An excerpt characterizing the Ecliptic
On Sunday morning, Marya Dmitrievna invited her guests to Mass at her parish of the Assumption on Mogiltsy.“I don’t like these fashionable churches,” she said, apparently proud of her free-thinking. “There is only one God everywhere. Our priest is fine, he serves decently, it's so noble, and so is the deacon. Is it any holiness from this that they sing concerts on the kliros? I do not like, one pampering!
Marya Dmitrievna loved Sundays and knew how to celebrate them. Her house was all washed and cleaned on Saturday; people and she did not work, everyone was festively discharged, and everyone was at mass. Meals were added to the master's dinner, and people were given vodka and a roasted goose or pig. But on nothing in the whole house was the holiday so noticeable as on the broad, stern face of Marya Dmitrievna, which on that day assumed an unchanging expression of solemnity.
When they had drunk coffee after mass, in the living room with the covers removed, Marya Dmitrievna was informed that the carriage was ready, and with a stern look, dressed in a ceremonial shawl in which she made visits, she got up and announced that she was going to Prince Nikolai Andreevich Bolkonsky to explain to him about Natasha.
After Marya Dmitrievna's departure, a fashionista from Madame Chalmet came to the Rostovs, and Natasha, having closed the door in the room next to the living room, very pleased with the entertainment, began trying on new dresses. While she, putting on a bodice that was still sleeveless, and bending her head back, looked in the mirror at how her back was sitting, she heard in the living room the lively sounds of her father’s voice and another, female voice, which made her blush. It was Ellen's voice. Before Natasha had time to take off the bodice she was trying on, the door opened and Countess Bezukhaya entered the room, beaming with a good-natured and affectionate smile, in a dark purple, high-necked velvet dress.
Ah, ma delicieuse! [Oh, my lovely!] - she said to the blushing Natasha. - Charmante! [Charming!] No, it's not like anything, my dear count, - she said to Ilya Andreevich, who came in after her. - How to live in Moscow and not go anywhere? No, I won't leave you! This evening m lle Georges is declaiming at my place and some people will gather; and if you don't bring your beauties, who are better than m lle Georges, then I don't want to know you. There is no husband, he went to Tver, otherwise I would have sent him for you. By all means come, by all means, at the ninth hour. She nodded her head at the familiar fashionista, who respectfully crouched down to her, and sat down on an armchair near the mirror, picturesquely spreading the folds of her velvet dress. She did not stop chatting good-naturedly and cheerfully, constantly admiring Natasha's beauty. She examined her dresses and praised them, and also boasted of her new dress en gaz metallique, [made of metal-colored gas] which she had received from Paris and advised Natasha to do the same.
“However, everything suits you, my lovely,” she said.
A smile of pleasure never left Natasha's face. She felt happy and flourishing under the praises of this dear Countess Bezukhova, who had previously seemed to her such an impregnable and important lady, and who was now so kind to her. Natasha became cheerful and felt almost in love with this beautiful and such good-natured woman. Helen, for her part, sincerely admired Natasha and wanted to amuse her. Anatole asked her to set him up with Natasha, and for this she came to the Rostovs. The thought of bringing her brother together with Natasha amused her.
In spite of the fact that she had previously been annoyed with Natasha for having wrested Boris from her in Petersburg, now she did not even think about it, and with all her heart, in her own way, wished Natasha well. Leaving the Rostovs, she withdrew her protegee aside.
- Yesterday my brother dined with me - we were dying of laughter - he does not eat anything and sighs for you, my charm. Il est fou, mais fou amoureux de vous, ma chere. [He's crazy, but he's crazy in love with you, my dear.]
Natasha blushed purple upon hearing these words.
- How blushing, how blushing, ma delicieuse! [my charm!] - Helen said. - You should definitely come. Si vous aimez quelqu "un, ma delicieuse, ce n" est pas une raison pour se cloitrer. Si meme vous etes promise, je suis sure que votre promis aurait desire que vous alliez dans le monde en son absence plutot que deperir d "ennui. [From the fact that you love someone, my lovely, you should not live as a nun. Even if you're a bride, I'm sure your fiancé would rather have you go out into the world in his absence than die of boredom.]
“So she knows that I am a bride, so she and her husband, with Pierre, with this fair Pierre, Natasha thought, talked and laughed about it. So it was nothing." And again, under the influence of Helen, what had previously seemed terrible seemed simple and natural. “And she is such a grande dame, [important lady,] so sweet and so evidently loves me with all her heart,” thought Natasha. And why not have fun? thought Natasha, looking at Helen with surprised, wide-open eyes.
Observation of the starry sky in all ages has served people to obtain the necessary information. We find astronomical tables among the Egyptians, the Sumerians, the Maya. According to them, ancient people determined the start time of agricultural work, river floods, solar and lunar eclipses, and created calendars. At the time of the great geographical discoveries, the stars served as the only guide for ships in the ocean. Therefore, astronomical knowledge was vital. Everyone who has ever been interested in astronomy has heard the name "ecliptic". This concept is found in describing the movement of celestial bodies, determining stellar coordinates. Consider what the ecliptic is.
Story
In ancient times, when people considered the Earth to be flat and covered with a heavenly bowl, the movement of the sun was explained in different ways. It was the god Ra among the Egyptians who sailed on his boat, or Helios among the Greeks ruled the chariot. But the path of these gods across the sky was repeated year after year.
In the geocentric system of the world of Ptolemy, the Sun revolved around the Earth along with other planets, and its path during the year was called the ecliptic of the sun. This imaginary line served as an important reference point for determining coordinates and was one of the main elements of the armillary sphere. With the help of the armillary sphere, stellar coordinates were determined, and the ecliptic on it usually represented a wide ring depicting the signs of the zodiac. What is the ecliptic in modern science?
Definition
After the discovery of Copernicus, it became clear that the movement of the Sun along the ecliptic, visible from the Earth, is explained by the movement of the Earth around the central luminary. But this concept has not ceased to exist. The word "ecliptic" comes from the ancient Greek "eclipsis", which means "eclipse". Only on this line solar and lunar eclipses are observed. Modern astronomy defines the ecliptic as the circle along which the sun moves throughout the year. To be more precise, this is the line of the section of the sphere by the plane of the orbit of the geometric center of the Earth-Moon pair.
Plane
The plane of the ecliptic forms the orbit of the Earth-Moon system during rotation around the Sun. The angle of inclination of the plane to the celestial equator is approximately 23 o. It changes over time. To calculate these changes, there is a special formula. Tilt angle fluctuations occur periodically - every 18.6 years. The range of variation is approximately 18.42". The tilt fluctuates every 40,000 years. All planets in the solar system have their own angle of the ecliptic.
Zodiac
In astronomy, the belt of the sky about 9 o on either side of the ecliptic is called the zodiacal belt. In it, the Sun passes through thirteen constellations. These are twelve well-known constellations of the ecliptic, accepted in astrology, and Ophiuchus.
For the first time, the zodiac circle is found in Babylon (Mesopotamia) in the 5th century BC. e. There, a sexagesimal calculus system was adopted, where a full circle is equal to 360 o. Initially, the Babylonians divided the sky into 36 sectors, then into 18 and 12. In each sector, a group of stars formed constellations. Each constellation was assigned special properties. Special points have been identified in the zodiac.
These are the spring equinox on March 21 (Pisces), the summer solstice on June 22 (Cancer), the autumn equinox on September 22 (Libra), and the winter solstice on December 22 (Capricorn).
Ophiuchus
The constellation Ophiuchus established itself on the ecliptic in the first half of the 20th century, when the boundaries and coordinates of the constellations were clarified. It is located between Scorpio and Sagittarius. Moreover, the Sun spends even more time in Ophiuchus than in Sagittarius. In the constellation of Ophiuchus, the last supernova in our Galaxy flared up in 1604. It was observed by Johannes Kepler. In 1848, a nova outburst was recorded. There are many interesting astronomical objects in the constellation Ophiuchus. This is a red dwarf - Barnard's star, many globular clusters and about 2500 variable stars. Scientists have discovered about 9 stars in this constellation.
Ecliptic coordinate system
Based on the ecliptic, there is a system of ecliptic stellar coordinates. The plane of the ecliptic was taken as the basis. Coordinates are defined between the plane and the pole of the ecliptic. The main coordinates are ecliptic latitude and ecliptic longitude. Latitude is the angle between the plane of the ecliptic and the object. Longitude is the angle between the vernal equinox and the plane of latitude.
Coordinate types
There are two types of ecliptic coordinates. In the first type, the center of the Earth is taken as the central point. Such a geocentric system is used mainly for calculations of lunar orbits. In the second type of coordinates, the center of the Sun is considered to be the center, and this system is used when calculating the orbits of the planets of the Solar System. Given the periodic fluctuations in the angle of the ecliptic, one must keep in mind the era when certain coordinates were determined. For this, the current coordinates of the ecliptic and Sun poles are constantly determined.
Zodiacal coordinate system
This coordinate system is used in astrology. The main coordinate here is the zodiacal position, which is calculated from the ecliptic longitude. Latitude is largely not used in this system. But in special cases it is defined in the same way as in astronomy. The annual motion of the Sun and the ecliptic serve as important indicators for astrology.
Astrology
At all times, people believed that human life is influenced by the location of heavenly bodies. Just as the development of chemistry was caused by the needs of alchemy, so the rapid development of astronomy in the Middle Ages was partly facilitated by astrology. Each constellation in astrology is credited with its own special influence on humanity as a whole and on each individual person. From the combination of the location of the constellations and planets, according to astrologers, literally everything depends - from a happy marriage to the state of financial markets. There are two major astrological systems - Western and Vedic. Each of them operates with its own postulates, and the conclusions from the same messages do not always coincide. Modern science does not recognize astrology, considering it pseudoscience. But each of us sometimes reads horoscopes. What is the ecliptic, in astrology, almost everyone knows
Flying in space
Many fantasy novels describe the adventures of spaceships, asteroids that fall into the belt, which is located between the orbits of Mars and Jupiter. Efremov, Strugatsky, Lem have such episodes. The asteroid belt, like all the planets of the solar system, rotates in the plane of the ecliptic. Maybe it's worth going beyond this plane and avoiding all possible collisions? Unfortunately, according to the laws of celestial mechanics, this requires a very large amount of energy and, accordingly, a large amount of additional fuel. In addition, it should be borne in mind that the return return will also require large energy costs. In the future, spacecraft with a solar sail that use the solar wind are considered.
In one of S. Lem's stories about the pilot Pirx, flights in this zone are generally prohibited, it is declared closed. Then it turns out that there is an alien spacecraft, which is carefully hidden. The calculation of interplanetary space orbits is a very difficult task. We have to solve the problem of at least three moving bodies, take into account the gravity of the planets and the peculiarities of their rotation. Spacecraft launched to other planets move along complex trajectories. The gravitational force of the planets is sometimes used to accelerate them.
Thus, the first probes Pioneer-10 and Pioneer-11, launched back in the 1970s, have already left the solar system under the influence of the gravity of Jupiter and Saturn. In all these calculations, the concept of the ecliptic plays a fundamental role. What is the ecliptic for interplanetary travel, it is not necessary to explain.
Plane of the ecliptic
The plane of the ecliptic is clearly visible in this image taken in 1994 by the Clementine Lunar Reconnaissance Spacecraft. Clementine's camera shows (from right to left) the Moon illuminated by the Earth, the glare of the Sun rising over the dark part of the Moon's surface, and the planets Saturn, Mars and Mercury (three dots in the lower left corner)
The name "ecliptic" is associated with the fact known since ancient times that solar and lunar eclipses occur only when the Moon is near the points of intersection of its orbit with the ecliptic. These points on the celestial sphere are called the lunar nodes. The ecliptic passes through the zodiac constellations and Ophiuchus. The plane of the ecliptic serves as the base plane in the ecliptic celestial coordinate system.
see also
Wikimedia Foundation. 2010 .
See what the "Plane of the ecliptic" is in other dictionaries:
The Laplace plane is a plane passing through the center of mass of the solar system perpendicular to the angular momentum vector, in other words, it is perpendicular to the vector of the total orbital momentum of all planets and rotational momentum ... ... Wikipedia
The celestial sphere is divided by the celestial equator. The celestial sphere is an imaginary auxiliary sphere of arbitrary radius onto which celestial bodies are projected: it serves to solve various astrometric problems. Behind the center of the celestial sphere, like ... ... Wikipedia
The celestial sphere is divided by the celestial equator. The celestial sphere is an imaginary auxiliary sphere of arbitrary radius onto which celestial bodies are projected: it serves to solve various astrometric problems. Behind the center of the celestial sphere, like ... ... Wikipedia
The fundamental plane is a plane, the choice of which (as well as the origin at a given point of this plane) determines various systems of spherical, geographical, geodetic and astronomical coordinates (including celestial ... Wikipedia
The plane passing through the center of mass of the solar system is perpendicular to the angular momentum vector. The concept of L. n. p. was introduced in 1789 by P. Laplace, who pointed out the advantages of using it as the main coordinate ... ... Great Soviet Encyclopedia
- (Eng. Deep Ecliptic Survey) a project to search for Kuiper belt objects using the facilities of the National Optical Astronomical Observatory (NOAO) at the Kitt Peak National Observatory. Project leader Bob Millis. The project operated from ... ... Wikipedia
The plane of the ecliptic is clearly visible in this image taken in 1994 by the Clementine Lunar Reconnaissance Spacecraft. Clementine's camera shows (from right to left) the Moon illuminated by the Earth, the glare of the Sun rising over the dark ... Wikipedia
The celestial sphere is divided by the celestial equator. The celestial sphere is an imaginary auxiliary sphere of arbitrary radius onto which celestial bodies are projected: it serves to solve various astrometric problems. Behind the center of the celestial sphere, like ... ... Wikipedia
The celestial sphere is divided by the celestial equator. The celestial sphere is an imaginary auxiliary sphere of arbitrary radius onto which celestial bodies are projected: it serves to solve various astrometric problems. Behind the center of the celestial sphere, like ... ... Wikipedia
