Presentation on astronomy celestial sphere starry sky. Starry sky: powerpoint presentation. Fragments from the presentation
FINAL TEST
1 option
1. Astronomy is...
a) the largest possible area of space, including all celestial bodies and their systems available for study;
b) the science of structure, movement, origin and development celestial bodies, their systems and the entire Universe as a whole;
c) science that studies the laws of the structure of matter, bodies and their systems;
2. 1 astronomical unit is equal to...
3. The main source of knowledge about celestial bodies, processes and phenomena occurring in the Universe are...
a) measurements; b) observations; c) experience; d) calculations.
4. On a dark moonless night you can see approximately
25,000 stars.
5. The celestial sphere was conventionally divided into...
a) 100 constellations; b) 50 constellations; c) 88 constellations; d) 44 constellations.
6. Does NOT apply to zodiac constellations...
a) Aries; marriage; c) Aquarius; d) Big dog.
7. The axis of the world intersects the celestial sphere at points called..
8. The plane passing through the center of the celestial sphere and perpendicular to the plumb line is called...
a) physical horizon; b) mathematical horizon;
c) zodiac belt; d) the equator.
9. The period of revolution of the Moon around the Earth relative to the stars is called...
10. The phases of the moon are repeated every….
11. In 1516, N. Copernicus substantiated the heliocentric system of the structure of the world, which is based on the following statement:
a) The sun and stars move around the Earth;
b) The planets move across the sky in a loop;
c) The planets, including the Earth, move around the Sun;
The celestial sphere revolves around the Earth.
12. Which scientist discovered the laws of planetary motion?
a) Galileo; b) Copernicus; c) Kepler; d) Newton.
13. Horizontal parallax has increased. How has the distance to the planet changed?
a) increased; b) decreased; c) has not changed.
14. What planets can be in opposition?
a) lower; b) upper; c) only Mars; d) only Venus.
15. The upper planets include:
16. The angular distance of a planet from the Sun is called...
a) connection; b) configuration; c) elongation; d) quadrature.
17. The period of time during which the planet makes a full revolution around the Sun in its orbit is called...
18. With eastern elongation inner planet visible on...
a) west; b) east; c) north; d) south.
19. Kepler's first law states that:
20. The angle at which the radius of the Earth was visible from the luminary is called...
a) western elongation; b) eastern elongation;
c) horizontal parallax; d) vertical parallax.
21. Which group of stars on the Hertzsprung-Russell diagram does the Sun belong to?
a) into a sequence of supergiants;
b) into a sequence of subdwarfs;
c) to the main sequence;
22. What color is a star of spectral type K?
a) white; b) orange; c) yellow; d) blue.
23. The sun produces energy by...
a) nuclear reactions; b) thermonuclear reactions;
d) speed atomic nuclei; d) radiation.
24. The sun consists of helium on...
25. Stefan-Boltzmann law -….
a) b) 
; c) d) .
26. Spots and faculae on the Sun are formed in...
a) zone thermonuclear reactions(core);
b) zone of radiant energy transfer;
c) convective zone;
d) photosphere.
27. The magnetic field of the Sun changes its direction every...
28. The sun belongs to the spectral class...
a) F; b) G; c) K; d) M.
29. Stars whose duality is revealed by deviations in the movement of a bright star under the influence of an invisible satellite are called...
c) astrometrically binary; d) spectroscopic doubles.
30. When everything is done nuclear fuel inside the star burns out, the process begins...
a) gradual expansion; b) gravitational compression;
c) formation of a protostar; d) pulsations of the star.
FINAL TEST
Option 2
1. The Universe is...
a) the science of the structure, movement, origin and development of celestial bodies, their systems and the entire Universe as a whole;
b) science that studies the laws of the structure of matter, bodies and their systems;
c) the largest possible area of space, including all celestial bodies and their systems available for study;
d) the science of matter, its properties and movement, is one of the most ancient scientific disciplines.
2. 1 pc (parsec) is equal to...
a) 150 million km; b) 3.26 St. years; c) 1 St. year; d) 100 million km.
3. An optical telescope that uses a system of lenses called an objective to collect light is called...
a) reflector; b) refractor; c) radio telescope; d) Hubble.
4. The entire celestial sphere contains about...
a) 3000 stars; b) 2500 stars; c) 6000 stars; d) 25,000 stars.
5. The faintest stars (according to Hipparchus) have...
a) 1 magnitude; b) 2nd magnitude;
c) 5th magnitude; d) 6th magnitude.
6. The apparent annual path of the center of the solar disk along the celestial sphere is called...
a) the celestial equator; b) ecliptic;
c) celestial meridian; d) zodiac belt.
7. A plumb line intersects the celestial sphere at two points called...
a) zenith and nadir; b) the poles of the world;
c) points of the spring and autumn equinox; d) climaxes.
8. The axis of apparent rotation of the celestial sphere is called...
a) a plumb line; b) the equator;
c) the axis of the world; d) celestial meridian.
9. The time interval between two successive phases of the Moon is called...
a) synodic month; b) lunar month;
c) sidereal month; d) solar month.
10. The Moon returns to the node of the same name in the lunar orbit through...
a) 29.53 days; b) 27.21 days; c) 346, 53 days; d) 24.56 days.
11. In what orbits do the planets move?
a) circular; b) hyperbolic; c) elliptical; d) parabolic.
12. How do the orbital periods of planets change as they move away from the Sun?
a) do not change; b) decrease; c) increase.
13. The first escape velocity is:
a) the speed of movement in a circle for a given distance relative to the center;
b) speed of movement along a parabola relative to the center;
c) circular speed for the Earth's surface;
d) parabolic speed for the Earth's surface.
14. When is the Earth closest to the Sun due to its annual orbital motion?
in the summer; b) at perihelion; c) in winter; d) at aphelion.
15. The lower planets include:
a) Mercury, Venus, Mars; b) Jupiter, Uranus, Neptune;
c) Venus and Mars; d) Mercury and Venus.
16. The characteristic positions of the planets relative to the Sun are called...
a) connections; b) configurations; c) elongations; d) quadratures.
17. When the angular distance of the planet from the Sun is 90 0, then the planet is in...
a) connection; b) configurations; c) elongation; d) quadrature.
18. The time interval between two identical configurations of the planet is called...
a) sidereal period; b) synodic period.
19. Kepler's second law states that:
a) each planet moves along an ellipse, at one of the foci of which the Sun is located;
b) The radius vector of the planet describes in equal time intervals equal areas;
c) The squares of the sidereal periods of revolutions of two planets are related as the cubes of the semimajor axes of their orbits.
20. Kepler’s third law, refined by Newton, is used mainly to determine...
a) distances; b) period; c) masses; d) radius.
21. The annual parallax is used for:
a) determining the distance to the nearest stars;
b) determining the distance to the planets;
c) the distance traveled by the Earth in a year;
d) proof of the finiteness of the speed of light.
22. The difference in the type of spectra of stars is determined first of all...
a) age; b) temperature;
c) luminosity; d) size.
23. Mass of the Sun from the total mass solar system amounts to...
a) 99.866%; b) 31.31%; c) 1.9891%; d) 27.4%.
24. The sun consists of hydrogen on...
a) 71%; b) 27%; at 2%; d) 85%.
25. Law of Wine -….
a) b) ; c) d) .
26. At the center of the Sun is...
a) thermonuclear reaction zone (core);
b) zone of radiant energy transfer;
c) convective zone;
d) atmosphere.
27. The period of activity of the Sun is...
a) 12 years old; b) 36 years old; c) 11 years old; d) 100 years.
28. The luminosity of a star is called...
a) the total energy emitted by the star per unit time;
b) the apparent magnitude that the star would have if it were at a distance of 10 pc from us;
c) the total energy emitted by the star during its existence;
d) apparent magnitude.
29. If the plane of revolution of stars around their common center of mass passes through the eye of the observer, then such stars are...
a) visually double; b) eclipsing binaries;
c) eclipsing binaries; d) spectroscopic doubles.
30. In a stationary state, the star on the Hertzsprung-Russell diagram is on...
A) main sequence; b) into a sequence of supergiants;
c) into a sequence of subdwarfs;
d) into the sequence of white dwarfs.
ANSWERS TO THE TEST WORK.
OPTION 1
OPTION 2
Slide 2
The night sky is one of the most beautiful spectacles in nature. Myriads of stars sparkle in the dark depths. Bright planets and tailed comets move between the stars
Slide 3
In 1608, the Dutchman Hans Lippershei created a telescope. However, the first person to use a telescope to study the starry sky was the Italian Galileo Galilei. He saw the moons of Jupiter, craters on the Moon and spots on the Sun. His telescope was very small. Later, optical instruments reached 50 meters in length.
Slide 4
What is the Solar System?
Our star - the Sun - has its own family; it includes 9 planets that revolve around the Sun. Stars are made of hot gases. What planets of the solar system do you know? What can you tell us about them?
Slide 5
neptune uranus Slide 6pluto marsd 9 Slide 12sun venus Slide 14jupiter saturn Slide 13earth mercury Slide 11moon
Slide 6
NEPTUNE According to established tradition, the eighth planet from the Sun was named after the ancient god. This honor went to the god of the seas, Neptune. In modern astrology, Neptune associated with water symbolizes the primordial principle from which feelings and emotions are born. He is the embodiment of memory, leading us into the depths of millennia.
Slide 7
URANUS Uranus is the seventh most distant planet from the sun and is named after the Greek God of the sky, Uranus. Uranus became the first planet discovered in modern times using a telescope.
Slide 8
PLUTO Pluto is the ninth planet of the solar system. This is the farthest famous planets Solar system. You can see it either in photographs or through a powerful telescope.
Slide 9
Venus is the second planet from the Sun. Its surface is inaccessible to optical observations from Earth, since the planet is shrouded in clouds.
There are constant winds blowing in the air. Near the surface their speed is insignificant, but increases with height. There are also active volcanoes on the planet VENUS
Slide 10
SATURN Saturn is the sixth planet of the solar system. Saturn is named after the Roman God of Agriculture. Saturn has a powerful ring system made of ice and dust particles.
Slide 11
Mars The fourth planet of the solar system. Many call it another “dead” planet or the red planet.
Slide 12
Mercury Mercury is the planet closest to the Sun. The ancient Romans considered Mercury the patron of trade, travelers and thieves, as well as the messenger of the gods. It is not surprising that a small planet, quickly moving across the sky following the Sun, received his name.
Slide 13
Moon Much has been written about the Moon and, perhaps, no other celestial body can compete with the Moon in the number of excellent photographic portraits, including those taken at close range from aboard automatic space stations. And yet Luna still does not want to part with her secrets.
Slide 14
The Sun is our daylight, the Sun, a powerful source of energy. Every second, such an amount of heat is emitted from its surface, which would be quite enough to melt a layer of ice a thousand kilometers thick surrounding a ball equal in size to the Earth. Already about 100 years ago, scientists were thinking about how to replenish the energy reserves so generously emitted by the Sun into space.
Slide 15
Earth Earth is neither the largest nor the smallest planet in the solar system. However, its position among other planets is unique. The Earth is on average 149.6 million kilometers away from the Sun, and it is this distance that provides the surface of our planet with a range of temperatures within which life can exist.
Slide 16 Jupiter Jupiter is a giant planet, the fifth from the Sun and the largest in the Solar System. A number of atmospheric phenomena on Jupiter - such as storms, lightning,, - have scales that are orders of magnitude greater than those on Earth
Slide 17
Quiz "Space"
This yellow star always warms us, illuminates all planets, protects us from other stars. Tiny - the planet is first warmed by the Sun, And agile - the year on it is Eighty-eight days.
Slide 18
There are miracles on the planet: Oceans and forests, Oxygen is in the atmosphere, People and animals breathe it.
It either loses weight or gets fatter, It shines from the sky, but does not warm, And it always looks at the Earth with only one side.
Slide 19
Yuri Alekseyevich Gagarin Yuri Alekseevich Gagarin - USSR pilot-cosmonaut, Hero Soviet Union
, Colonel, the first person to fly into outer space.
Slide 20
Slide 21
The street is full of ordinary noise, Spring is coming, the working day is in full swing, And from the Universe a radio wave Brings a name to everyone: Gagarin! It bursts into everything, flies into all hearts like a swallow. And Mother Earth, holding her breath, watches the flight of the hero-son.
Slide 22
Valentina Tereshkova
Valentina Tereshkova is the first female cosmonaut. She was not afraid, she boldly stepped onto the cosmic path. She did her job with honor and proved that women are capable of much, and even of flying into space. We are proud of those people who have connected their lives with the dangerous, difficult, but noble cause of space flight.
Slide 23
Nutrition for astronauts.
Food: Tubes of food for ISS workers are a thing of the past. Now they eat pre-freeze-dried (dehydrated) food, which they choose from a special menu. Presentation on the topic "Starry sky" on astronomy in powerpoint format. Beautifully illustrated and filled interesting facts
about stars and constellations. Presentation authors: Roman Erofeev and Vladimir Boryushkin, 11th grade students.
Fragments from the presentation On a cloudless and moonless night far from settlements
About 3000 stars can be distinguished. The entire celestial sphere contains about 6,000 stars visible to the naked eye. The most famous group of stars in the northern hemisphere is Ladle.
Ursa Major
Ancient astronomers divided the starry sky into constellations. Most of the constellations named during the times of Hipparchus and Ptolemy are named after animals or heroes of myth. Thousands of years ago bright stars conditionally connected into figures that were called
constellations.
A constellation is a section of the celestial sphere, the boundaries of which are determined by a special decision of the International Astronomical Union (IAU). In total there are 88 constellations on the celestial sphere.
The brightest stars have their own names.
The constellation Ursa Major can serve a good helper to remember the brightest stars of the Northern Hemisphere.
It is easy to determine the northern direction from the Ursa Major bucket.
Before the invention of the compass, the stars were the main landmarks: it was by them that ancient sailors and travelers found the right direction. Celestial navigation (orientation by the stars) has retained its importance in our age of satellites and atomic energy. It is necessary for navigators and cosmonauts, captains and pilots. The 25 brightest stars are called navigation stars, with the help of which the location of the ship is determined.
Lesson 1-2
Lesson topic: From the history of astronomy.Celestial sphere. starry sky.
Lesson objectives:
- Introduce students to the history of the development of the science of astronomy; characterize the main branches of science; introduce basic concepts: celestial sphere, axis mundi, equator, ecliptic, etc.
- Continue to develop the student’s views on the universe
Equipment: presentation " From the history of astronomy.Celestial sphere. Starry sky"; disk
During the classes
Organizational moment.
Learning new material
Astronomy- the science of the Universe that studies the structure, origin and development of celestial bodies and systems.
A) From the history of astronomy
1. Aristotle in the 4th century. BC e. believed that the Earth was in the center of the world, and the Sun, Moon, and stars were attached to transparent crystal spheres and revolved around it. Observing lunar eclipses, he concluded that the Earth has a spherical shape. The earthly world, according to Aristotle, consists of earth, air, water and fire. The heavenly world consists of a special substance - pleena , some semblance of ether.
2. In the II century. n. e. The Alexandrian astronomer Ptolemy, based on the ideas of Aristotle and other scientists, created a geocentric system of the world.
According to Ptolemy's theory, the number of celestial spheres is 55. The geocentric system of the world could not explain the movement of the planets and a number of other observed phenomena.
3. N. Copernicus in 1543 published the book “On the Revolution of the Heavenly Circles,” in which he showed that the movement of celestial bodies can be easily explained on the basis of the heliocentric system of the world, according to which the Sun is at the center of the world. Copernicus and his students made calculations of the future positions of celestial bodies, which turned out to be quite accurate.
The teachings of Copernicus were rejected Catholic Church, who saw in it a contradiction with the Bible, which stated that man is at the center of the Universe.
4. Giordano Bruno added a number of new ideas to the teachings of Copernicus. According to Bruno, there are many solar-like systems in the Universe. Planets revolve around stars. Stars are born and die, so life in the Universe is endless.
Giordano Bruno was declared a heretic, hid for several years, and the Inquisition lured him to Italy by deception. Giordano Bruno was demanded to renounce his views, but he continued to insist on the justice of his ideas and on February 17, 1600 he was executed in Rome. This execution not only did not stop the spread of Bruno's ideas, but, on the contrary, aroused great public interest in them.
5. In 1557, the Danish astronomer Tycho Brahe discovered errors in Copernicus' calculations. In 1577 he calculated the positions of comets. The results he obtained also contradicted Ptolemy’s theory, according to which comets appear in the empty space between the Moon and the Earth.
Tycho Brahe created a planetary system and compiled a large catalog of fixed stars. To help with the calculations, he invited Johannes Kepler and set him the task of determining the trajectory of the planets.
6. After the death of Tycho Brahe, Johannes Kepler continued to work on analyzing the huge amount of observational results that Brahe left him.
7. On November 10, 1619, in Bavaria, Rene Descartes decided to create analytical geometry and use mathematical methods in philosophy. Main principle he expressed his philosophy as follows broadly famous aphorism: “I think, therefore I exist.”
Any expressed ideas, according to Descartes, are true if they are clear and definite. He viewed the entire Universe as a mechanism. God created matter and endowed it with movement, after which the world began to develop according to the laws of mechanics. From a world consisting of material particles, Descartes created the Copernican Universe as we observe it. So, by the middle of the 16th century. The universe has gone from closed to open, mostly empty, in which particles move and collide, and between two collisions they move at a constant speed.
8. In 1632, the Italian scientist Galileo Galilei published the book “Dialogue of Two major systems world - Ptolemy and Copernicus."
In this book, Copernicus's heliocentric system clearly defeated Ptolemy's geocentric system. Galileo himself was a supporter of the heliocentric system, since his observations of the Sun, Moon, Venus and Jupiter using the telescope he created showed the presence of satellites of Jupiter, the existence of phases of Venus similar to the lunar ones, and the fact that the Sun rotates around an axis. All his observations showed that the Earth does not have any special advantages, but behaves in the same way as other planets.
Galileo was summoned to the Inquisition, where, under pain of torture and execution, he renounced the “heresy”, strict supervision was established over him, and he could no longer engage in research. (In 1982, Pope John Paul admitted the church's mistake and cleared Galileo of all charges.)
9. The final triumph of the heliocentric system came after the discovery of the law by I. Newton universal gravity. Based on this law, it was possible to derive Kepler's laws and give an accurate description of the movement of celestial bodies.
10. But, despite the harmony and argumentation of Newton’s theory, there was a phenomenon that confirmed doubts about the daily rotation of the Earth. If the Earth rotated, the position of the stars would have to change. However, there seemed to be no change. The first experimental proof of the Earth's motion around the Sun was made in 1725 by the English astronomer James Bradley. He discovered the displacement of stars. The stars are shifted from the average position by 20" in the direction of the Earth's velocity vector (the phenomenon of light aberration).
In 1837, Russian astronomer V.Ya. Struve measured the annual parallax of the star Vega, which made it possible to determine the speed of rotation of the Earth.
Currently, no one doubts the fact that the Earth rotates around own axis and its rotation around the Sun. Based on these facts, many phenomena occurring on Earth are explained.
11. Most active development astronomy dates back to the twentieth century. This was facilitated by the creation of high-resolution optical and radio telescopes, as well as the possibility of research with artificial satellites Earths that allowed observations outside the atmosphere.
It was in the twentieth century. the world of galaxies was discovered. The study of the spectra of galaxies allowed E. Hubble (1929) to detect the general expansion of the Universe predicted by A.A. Friedman (1922) based on A. Einstein’s theory of gravity. New types of cosmic bodies were discovered: radio galaxies, quasars, pulsars, etc.
The foundations of the theory of the evolution of stars and the cosmogony of the Solar System were also developed. The largest achievement of astrophysics of the twentieth century. became relativistic cosmology - the theory of the evolution of the Universe as a whole.
Otto Yulievich Schmidt(1891 - 1956) - Russian scientist, statesman, one of the organizers of the development of the Northern Sea Route.
He was the organizer and leader of many expeditions to North Pole, in particular, expeditions on the Sedov (1929 - 1930), Sibiryakov (1932), Chelyuskin (1933 - 1934), an air expedition to organize the drifting station SP-1 (1937).
Developed cosmogonic hypothesisformation of solar system bodies as a result of condensation of a circumsolar gas-dust cloud. Works on higher algebra (group theory).
In 1935 O.Yu. Schmidt was elected academician from 1935 to 1942. was vice-president of the USSR Academy of Sciences.
In 1937 he was awarded the title Hero of the Soviet Union. In 1932 - 1939 was the head of the Main Northern Sea Route. The enormous merit of O.Yu. Schmidt was the creation of the Big Soviet Encyclopedia, of which he was the founder and editor-in-chief from 1924 to 1942.
Fred Hoyle (b. 1915) - English astrophysicist.
Works on stellar and planetary cosmogony, theories internal structure and evolution of stars, cosmology.
B) Sections of astronomy
- Astrometry - the science of measuring space and time.
- Theoretical astronomy– provides methods for determining the orbits of celestial bodies from their apparent positions, and methods for calculating ephemerides from known elements of their orbits.
- Celestial mechanics- studies the laws of motion of celestial bodies under the influence of the forces of universal gravity, determines the masses and shape of celestial bodies and the stability of their systems.
- Astrophysics - studies the structure, physical properties And chemical composition celestial objects.
- Stellar astronomy- studies the patterns of spatial distribution and movement of stars, star systems and interstellar matter.
- Cosmogony - examines issues of the origin and evolution of celestial bodies
- Cosmology - studies the general laws of the structure and development of the Universe.
B) Starry sky
On a dark night we can see about 2500 stars in the sky, which differ in brightness and color. It seems they are attached to the celestial sphere and revolve around the Earth with it. To navigate among them, the sky was divided into 88 constellations. In the 2nd century BC. Hipparchus divided stars according to their brightness into stellar magnitudes; he classified the brightest as stars of the first magnitude, and the weakest, barely visible with the naked eye, as stars of the sixth magnitude.
A special place among the constellations is occupied by 12 zodiacal ones, through which the annual path of the Sun passes - the ecliptic.
Constellations is a set of bright stars connected into shapes named after characters from ancient myths and legends, animals or objects.
The stars of the constellations are designated by letters of the Greek alphabet.
α is the brightest star in the constellation; β - less bright; γ - less bright, than β; δ, ε, ζ, etc.
In some constellations, the brightest stars have proper names, for example, Vega (α-star in the constellation Lyra), Deneb (α-star in the constellation Cygnus).
D) Basic concepts
Celestial sphere - this is an imaginary sphere of an arbitrarily large radius, in the center of which is the eye of the observer.
PP axis 1 apparent rotation of the celestial sphere is called axis of the world.
The plane passing through the center of the celestial sphere and perpendicular to the axis of the world is calledcelestial equator.
The circle in which the Sun rotates is deviated from the celestial equator by 23.5° and is called ecliptic
Right ascension- the angle measured along the celestial equator in the direction opposite to the daily rotation of the celestial sphere is denoted by the Greek letter α. The counting of right ascensions is done from the point of the celestial sphere on the day of the vernal equinox (γ), which is the center of the Sun on March 21.
The great circle of the celestial sphere passing through the poles of the world and the observed star is calledaround the declination.
The angular distance of the luminary from the equatorial plane, measured along the declination circle, is calleddeclination of the luminaryand is denoted by the letter δ.
Parallacticcalled the displacement of stars closer to Earth relative to more distant ones.
Parallax called the angle π at which the radius of the earth's orbit is visible.
1. The observer is located in the middle latitudes of the northern hemisphere. Star 1 – non-setting; 2 and 3 - descending and ascending; 4- non-ascending.
2. The observer is at the north pole of the Earth. Stars 1-3 are not setting; 4 and 5 – non-ascending. All stars move in planes parallel to the horizon; the plane of the horizon coincides with the plane of the celestial equator; the plumb line coincides with the axis of the world.
3. The observer is located at the equator. All stars are rising and setting in planes, perpendicular to the plane horizon; The axis of the world lies in the horizontal plane. In one day, an observer could see all the celestial bodies.
The climax The phenomenon of the passage of luminaries through the celestial meridian is called. At the upper culmination, the angular height of the star above the horizon is maximum, at the lower culmination it is minimum.
True noon- the moment of the upper culmination of the center of the Sun. True midnight is the moment of the lower culmination of the center of the Sun.
At true noon, the shadow of a vertical object falls along the noon line.
In a given area, the stars culminate at the same height above the horizon.
The Sun and Moon change the height of the climax.
During its annual movement along the ecliptic, the Sun crosses the celestial equator twice a year (March 21 and September 23).
View disc “All the secrets of space part 4” - (2,3)
At home: notes, reports “Determination of distances in astronomy”
PTOLEMY Claudius (c. 90 – c. 160), ancient Greek scientist, the last major astronomer of antiquity. He built special astronomical instruments: an astrolabe, an armillary sphere, and a triquetra. Described the position of 1022 stars. Ptolemy's system is set out in his main work "Almagest" ("Great mathematical construction astronomy in the XIII books") - an encyclopedia of astronomical knowledge of the ancients. Ancient astronomers divided the starry sky into constellations. Most of the constellations named during the times of Hipparchus and Ptolemy are named after animals or heroes of myth. HIPPARCHUS (c. 180 or 190 - 125 BC), ancient Greek astronomer, one of the founders of astronomy. He compiled a star catalog of 850 stars and recorded their brightness using the magnitude scale he introduced. He distributed all the stars into 28 constellations.
Thousands of years ago, bright stars were conventionally connected into figures, which were called constellations of the Ophiuchus and Serpens constellations from the Flamsteed atlas.
Images of constellations from the ancient atlas of Hevelius "Taurus" "Whale" "Cassiopeia"
Before the invention of the compass, the stars were the main landmarks: it was by them that ancient travelers and sailors found the right direction. Celestial navigation (orientation by the stars) has retained its importance in our age of satellites and atomic energy. It is necessary for navigators and astronauts, captains and pilots. The 25 brightest stars are called navigation stars, with the help of which the location of the ship is determined.
It is interesting that: Only in 58 constellations the brightest stars are called α (alpha). In 13 constellations, the brightest stars are β (beta), and in some others, other letters of the Greek alphabet are also present. The largest size is the constellation Hydra (1303 square degrees). The Southern Cross constellation has the smallest dimensions (68 square degrees). The constellation has the largest size visible in the northern hemisphere Big Dipper(1280 square degrees). The most big number stars brighter than the second magnitude contains the constellation Orion - 5 stars. The largest number of stars brighter than fourth magnitude is contained in the constellation Ursa Major - 19 stars.
