Starry sky throughout the year. Changing the appearance of the starry sky during the day outline of the lesson in astronomy (Grade 11) on the topic
The theme of the lesson is "Change in the appearance of the starry sky during the year." The purpose of the lesson: To study the apparent annual movement of the Sun. The starry sky is the great book of nature. Who will be able to read it, before that, countless treasures of the cosmos will be revealed. On a cloudless and moonless night away from settlements I distinguish about 3000 stars. The entire celestial sphere contains about 6,000 stars visible to the naked eye. You see one of the oldest Stonehenge observatories, and these are modern telescopes on Mauna Kea in Hawaii. Astronomers of antiquity divided the starry sky into 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. In total, there are 88 constellations in the celestial sphere. Most of constellations named in the time of Hipparchus and Ptolemy, has the name of animals or heroes of myths. To understand the apparent annual movement of the Sun, we need a map of the "Starry Sky". During the year, the Sun moves in a large circle of the celestial sphere. This great circle is called the ecliptic. The entire ecliptic of the Sun takes exactly one year. The constellations through which the ecliptic passes are called zodiacal, their number corresponds to the number of months in a year. So, together with the Sun, we set off on a journey through the zodiac constellations, paying attention to the bright stars in them. Aries. We will begin our journey on the day of the vernal equinox, (March 21) from the point of intersection of the ecliptic and the celestial equator. The brightest star in the constellation Aries is Gamal. (find a bright star) Taurus. In the eastern part of the sky, the constellation TAURUS flaunts. In the form of a calf, the ancient Greeks honored Zeus, the legend says that Zeus turned into a bull to kidnap the Phoenician princess Europa, while she and her friends were playing on the seashore. The brightest star in this constellation is Aldebaran. (find a bright star)
Gemini are two true friends. These are the Dioscuri Brothers (youths of God) CASTOR and POLLUX. There is a belief that they tame storms at sea, appearing on the tops of the masts of ships in the form of flames. (find a bright star) We have climbed the ecliptic to the maximum and are at the point of the summer solstice, having entered the constellation of Cancer (06/22), this day is the longest day. In the center of the constellation Cancer there is a star cluster Nursery. The philosopher Plato suggested that this is a hole in the "firmament of heaven", through which the souls of newborn babies descend to earth. The lion, according to legend, lived near the ancient Greek city of Nemea and devastated the surroundings. No one was able to kill him, as his skin was as hard as steel. Performing his first of twelve labors, Hercules stunned the beast and freed the city from its atrocities. (find a bright star) VIRGO. For many centuries, the appearance of the Virgin in the evening sky coincided with the harvest. Spica is "ear". Virgo is Athena, the goddess of fertility and peaceful labor. She taught people how to work. Athena is the patroness of science and the goddess of wisdom. The feast of Athena (Minerva) was celebrated by artisans and teachers, who then received payment for the education of children. And today, Teacher's Day is celebrated in the fall. (find a bright star) We cross the ecliptic again, on September 23, the day of the autumn equinox, i.e. day equals night. SCALES. Scales belong to the goddess of justice Dika. From the sting of Scorpio, at the behest of the Goddess of the hunt, Orion died. Sagittarius is the only one of the centaurs who was fair, wise and friendly to people. (find a bright star) Capricorn. Aquarius. Fish. The gods settled in the sky A flock of FISH and CAPRICORN, AND DOLPHIN, and WHALE, But they all need water! Then they called AQUARIUS, Pours and pours, he does not regret! Everything around was flooded with water, Therefore, on the side of that, there are very few conspicuous Stars Barely shining half-heartedly. December 22, winter solstice long night in a year. The constellation Capricorn begins with it. We have walked a circle around the sky. Crossed the ecliptic twice.
The ecliptic and the celestial equator intersect at the vernal equinox (March 21, Aries) and the autumnal equinox (September 23, Libra). On the day of the summer solstice (June 22) the sun rises to its maximum and on the day of the winter solstice (December 22) it descends to the plane of the celestial equator as much as possible. (identify the sun in these cards in your cards. And now three magic stars are being played. They will go to those who carefully traveled through the zodiac constellations, so: 1. Which star illuminates the bright talent of A. Pugacheva and all those who were born under this sign? (Gamal ) contributing to the manifestation of talent, (Magic star, you get it too) 2. Who knows, maybe it was this star in the constellation of Taurus that contributed to the development of mystical plots in the novel “The Master and Margarita” by Mikhail Bulgagov (aldebaran) (The magic star of eternal youth goes to you) 3. This star illuminates the path of the elected President of Russia D. Medvedev and all those who were born under the sign of VIRGO (Spica) (And may this star bring you good luck in the next elections) Astronavigation (orientation by the stars) has retained its significance in our age of satellites and atomic energy.It is necessary for navigators and astronauts, captains and pilots.Since ancient times, the polar star has been a guiding star for travelers, h to find it, you need to start by searching for the constellation Ursa Major. Its seven bright stars are just part of the largest constellation. But some imagination is already required to see a giant bear in all the other, fainter stars. Putting aside 5 times equal segments, we connect an imaginary line with the polar star. Below the polar star on the horizon is the north point. Knowing this, it is easy to navigate the terrain, find the cardinal points (north, south, east, west). (Find) Let's summarize. 1. How many constellations is the sky divided into? (88) 2. What is the ecliptic? (During the year, the Sun moves in a great circle of the celestial sphere. This great circle is called the ecliptic.) 3. At what points does the ecliptic and the celestial equator intersect?
(spring equinox on March 21 (Aries) and autumn equinox on September 23 (Libra) 4. What constellations are called zodiac? (The constellations through which the ecliptic passes are called zodiac) Why does the starry sky change during the year? Yes, because our dear planet , every day and every hour makes a revolution, and from the Earth, when observed, it seems that it is not she who is spinning, but all the stars and the moon.I hope you are carried away by astronomy because starry sky this is a whole world, its silent beauty and mystery fascinates everyone. There is a belief that if you look at the starry sky often and for a long time, then one day the Universe can reveal to you all the secrets of the universe. With the star chart you now have, you can quickly determine which constellations and bright stars are visible on a given evening. For the lesson, you get excellent grades, with the wish to LIVE ON THIS EARTH, DO NOT EXIT YOURSELF, and SHINE EVERYONE IN THE DARKNESS!
Change in the appearance of the starry sky during the year
Target : Get acquainted with the equatorial coordinate system, the visible annual movements of the Sun and the types of the starry sky (changes during the year), learn how to work according to the PKZN.
Tasks:
- 1st level (standard)- geographical and equatorial coordinates, points in the annual motion of the Sun, the inclination of the ecliptic.
- 2nd level- geographic and equatorial coordinates, points in the annual motion of the Sun, the inclination of the ecliptic, directions and causes of the displacement of the Sun above the horizon, zodiacal constellations.
Be able to:
- 1st level (standard)- set according to the PKZN for various dates of the year, determine the equatorial coordinates of the Sun and stars, find the zodiac constellations.
- 2nd level- set according to the PKZN for various dates of the year, determine the equatorial coordinates of the Sun and stars, find the zodiac constellations, use the PKZN.
Equipment: PCZN, celestial sphere. Geographic and star map. Model of horizontal and equatorial coordinates, photos of starry sky views at different times of the year. CD- "Red Shift 5.1" (the path of the Sun, Change of seasons). Video film "Astronomy" (part 1, fr. 1 "Star landmarks").
Interdisciplinary connection: Daily and annual movement of the Earth. The moon is a satellite of the Earth (natural science, 3-5 cells). Natural and climatic patterns (geography, 6 cells). Circular motion: period and frequency (physics, grade 9)
During the classes:
I. Student survey (8 min). You can test on the Celestial sphere:
- 1. At the board:
- 1. Celestial sphere and horizontal coordinate system.
- 2. The movement of the luminary during the day and the culmination.
- 3. Translation of hourly measure into degrees and vice versa.
- 2. 3 people on cards:
K-1
- 1. In which side of the sky is the luminary with horizontal coordinates: h=28°, A=180°. What is its zenith distance? (north, z=90°-28°=62°)
- 2. Name three constellations visible today during the day.
K-2
- 1. In which side of the sky is the star, if its coordinates are horizontal: h=34 0 , A=90 0 . What is its zenith distance? (west, z=90°-34°=56°)
- 2. Name three bright stars visible to us during the day.
K-3
- 1. In which side of the sky is the star, if its coordinates are horizontal: h=53 0, A=270 o. What is its zenith distance? (east, z=90°-53°=37°)
- 2. Today the star is in its upper climax at 21:34. When is its next lower, upper climax? (after 12 and 24 hours, more precisely after 11 h 58 m and 23 h 56 m)
- 3. The rest (on their own, while answering at the blackboard)
- a) Convert to degrees 21h34m, 15h21m15s. =(21.150+34.15"=3150+510"=323030", 15h21m15s=15.150+21.15"+15.15"=2250 + 315" + 225"= 230018"45")
- b) Convert to hourly measure 05o15", 13o12"24". = (05o15"=5.4m+15.4c=21m, 13o12"24"=b13.4m+12.4c+24.1/15c=52m+48c+1.6c = 52m49s,6)
II. new material(20 min) Video film "Astronomy" (part 1, fr. 1 "Star landmarks").
b) The position of the luminary in the sky (celestial medium) is also uniquely determined - in equatorial coordinate system, where the celestial equator is taken as a reference point . (equatorial coordinates were first introduced by Jan Havelia (1611-1687, Poland), in a catalog of 1564 stars compiled in 1661-1687) - an atlas of 1690 with engravings and is now used (textbook title).
Since the coordinates of the stars do not change for centuries, therefore, this system is used to create maps, atlases, catalogs [lists of stars]. The celestial equator is a plane passing through the center of the celestial sphere perpendicular to the axis of the world.
Figure 1 - Celestial equator
points E-east, W-west - the point of intersection of the celestial equator with the points of the horizon. (Points N and S come to mind).
All daily parallels of celestial bodies are parallel to the celestial equator (their plane is perpendicular to the axis of the world).
Declension circle - a large circle of the celestial sphere passing through the poles of the world and the observed luminary (points P, M, P ").
Equatorial coordinates:
d(delta) - declination of the luminary - the angular distance of the luminary from the plane of the celestial equator (similar to c).
b(alpha) - right ascension - angular distance from the vernal equinox ( G) along the celestial equator in the direction opposite to the daily rotation of the celestial sphere (in the direction of the Earth's rotation), up to the circle of declination (similar to l measured from the Greenwich meridian). It is measured in degrees from 0 o to 360 o, but usually in an hourly measure.
Table 1 - Celestial phenomena arising from cosmic phenomena
space phenomena |
Celestial phenomena arising from these cosmic phenomena |
Rotation of the Earth around its axis |
Physical phenomena:
Displays of the true rotation of the Earth around its axis:
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Rotation of the Earth around the Sun |
Displays of the true rotation of the Earth around the Sun:
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c) The annual movement of the Sun. There are luminaries [Moon, Sun, Planets] whose equatorial coordinates change rapidly. The ecliptic is the apparent annual path of the center of the solar disk across the celestial sphere. Tilt to the plane of the celestial equator is currently at an angle 23 about 26". The apparent motion of the Sun along the ecliptic is a reflection of the actual motion of the Earth around the Sun (proved only in 1728 by J. Bradley by the discovery of annual aberration).
The constellations through which the ecliptic passes are called the zodiac.
The number of zodiac constellations (12) is equal to the number of months in a year, and each month is indicated by the sign of the constellation in which the Sun is in that month.
13th constellation Ophiuchus excluded, even though the sun passes through it. "Red Shift 5.1" (the path of the Sun).
Sun coordinates: b =0 h, d =0 o
The designation has been preserved since the time of Hipparchus, when this point was in the constellation ARIES\u003e now it is in the constellation PISCES, In 2602 it will move into the constellation AQUARIUS.
-summer solstice. 22nd of June (the longest day and the shortest night).
Sun coordinates: b =6 h, \u003d + 23 about 26 "
The designation has been preserved since the time of Hipparchus, when this point was in the constellation of Gemini, then it was in the constellation of Cancer, and since 1988 it moved into the constellation of Taurus.
Sun coordinates: b =12 h, d =0 o
The designation of the constellation Libra was preserved as the designation of the symbol of justice under the emperor Augustus (63 BC - 14 AD), now in the constellation Virgo, and in 2442 it will move to the constellation Leo.
- winter solstice. December 22 (the shortest day and the longest night).
Sun coordinates: b =18 h, d =-23 about 26"
During the period of Hipparchus, the point was in the constellation of Capricorn, now in the constellation of Sagittarius, and in 2272 it will move into the constellation of Ophiuchus.
Figure 2 - The culmination of the position of the Sun
Although the position of the stars in the sky is uniquely determined by a pair of equatorial coordinates, the view of the starry sky at the place of observation at the same hour does not remain unchanged.
Observing at midnight the culmination of the luminaries (the Sun at this time is in the lower climax with right ascension on a different luminary from the climax), you can see that in different dates at midnight, near the celestial meridian, different constellations pass, replacing each other. [These observations at one time led to the conclusion about the change in the right ascension of the Sun.]
Let's choose any star and fix its position in the sky. At the same place, the star will appear in a day, more precisely, in 23 hours 56 minutes. A day measured relative to distant stars is called stellar (to be quite precise, a sidereal day is the time interval between two successive upper climaxes of the vernal equinox point). Where do the other 4 minutes go? The fact is that due to the movement of the Earth around the Sun, it shifts for an earthly observer against the background of stars by 1 ° per day. To "catch up" with him, the Earth needs these 4 minutes. (picture).
Each subsequent night, the stars shift slightly to the west, rising 4 minutes earlier. In a year it will shift by 24 hours, that is, the view of the starry sky will be repeated. The entire celestial sphere will make one revolution in a year - the result of a reflection of the revolution of the Earth around the Sun.
So, the Earth makes one rotation around its axis in 23 hours 56 minutes. 24 hours - the average solar day - the time of revolution of the Earth relative to the center of the Sun.
III. Fixing the material (10 min)
- 1. Work on the PKZN (in the course of presenting new material)
- a) finding the celestial equator, ecliptic, equatorial coordinates, equinox and solstice points.
- b) determining the coordinates of, for example, stars: Chapel (b Charioteer), Deneb (b Cygnus) (Capella - b \u003d 5 h 17 m, d \u003d 46 o; Deneb - b \u003d 20 h 41 m, d \u003d 45 o 17 ")
- c) finding stars by coordinates: (b \u003d 14.2 h, d \u003d 20 o) - Arcturus
- d) find where the Sun is today, in which constellations in the fall. (now the fourth week of September is in Virgo, the beginning of September is in Leo, Libra and Scorpio will pass in November
- 2. Additionally:
- a) The star culminates at 14:15. When is its next lower, upper climax? (after 11:58 and 23:56, that is, at 2:13 and 14:11).
- b) AES flew across the sky from the starting point with coordinates (b=18 h 15 m, d=36 o) to the point with coordinates (b=22 h 45 m, d=36 o). Through which constellations did the satellite fly.
IV. Lesson summary
- 1. Questions:
- a) What is the need to introduce equatorial coordinates?
- b) What are the remarkable days of the equinox, solstice?
- c) At what angle is the plane of the Earth's equator inclined to the plane of the ecliptic?
- d) Is it possible to consider the annual movement of the Sun along the ecliptic as proof of the revolution of the Earth around the Sun?
- 2. Ratings
Homework:
Practical work No. 1 (it is advisable to distribute this list of works with explanations to all students for a year).
Can be given an assignment 88 constellations "(one constellation for each student). Answer the questions:
- 1. What is the name of this constellation?
- 2. At what time of the year is it best to observe it at our (given) latitude?
- 3. What type of constellations does it belong to: non-ascending, non-setting, setting?
- 4. Is this a northern, southern, equatorial, zodiac constellation?
- 5. Name interesting objects of this constellation and indicate them on the map.
- 6. What is the name of the brightest star in the constellation? What are its main characteristics?
- 7. Using a mobile map of the starry sky, determine the equatorial coordinates of the brightest stars in the constellation.
Topic: Changing the appearance of the starry sky during the day.
Target: To acquaint students with the celestial environment and its rotation, orientation in the sky. Consider the horizontal coordinate system, the change in coordinates and the concept of the culmination of the luminaries, the conversion of a degree measure into an hour and vice versa.
Tasks :
1. Educational : introduce concepts: daily movement of the luminaries; celestial sphere and horizontal coordinate system; precessions; setting, non-ascending, non-setting luminaries; culmination, to continue the formation of the ability to work with the PKZN and astronomical ways of orienting the terrain by the stars. About astronomical research methods, astronomical observations and measurements and goniometric astronomical instruments (altimeter, theodolite, etc.). O cosmic phenomenon- the rotation of the Earth around its axis and its consequences - celestial phenomena: sunrise, sunset, daily movement and culminations of the luminaries (stars).
2.
nurturing : to promote the formation of the skill of identifying cause-and-effect relationships, about practical ways to apply astrometric knowledge.
3.
Educational : using problem situations, bring students to an independent conclusion that the view of the starry sky does not remain the same throughout the day, the formation of computational skills in translating degrees into hours and vice versa. Formation of skills: use a moving map of the starry sky, star atlases, the Astronomical calendar to determine the position and conditions for the visibility of celestial bodies and the flow of celestial phenomena; find the North Star in the sky and navigate by it on the ground.
Know:
1st level (standard)- the concept of the celestial sphere and the direction of rotation of the sky, the characteristic points and lines of the celestial sphere, the celestial meridian, the vertical, the horizontal coordinate system, the zenith distance, the concept of the culmination of the luminary and precession, the conversion of a degree measure into an hour and vice versa. Use goniometric astronomical instruments: theodolite, altimeter. Find in the sky the main constellations and the brightest stars visible at this time of the year at a given time in a given area.
2nd level - the concept of the celestial sphere and the direction of rotation of the sky, the characteristic points and lines of the celestial sphere, the celestial meridian, the vertical, the horizontal coordinate system, the zenith distance, the concept of the culmination of the luminary and their division, precession, conversion of degrees to hours and vice versa. Use goniometric astronomical instruments: theodolite, altimeter. Find in the sky the main constellations and the brightest stars visible at this time of the year at a given time in a given area.
Be able to:
1st level (standard)- build a celestial sphere with a mark of characteristic points and lines, show horizontal coordinates on the sphere, daily parallels of stars, show culmination points, perform the simplest conversion of hourly measure into degrees and vice versa, show constellations and bright stars on the PKZN, apply knowledge of basic concepts to solve quality objectives. Find the North Star in the sky and navigate the terrain using the North Star.
2nd level - build a celestial sphere with a mark of characteristic points and lines, show horizontal coordinates on the sphere, daily parallels of stars according to their division, show culmination points and zenith distance, convert hourly measure to degrees and vice versa, find constellations and bright stars, culmination of stars using PKZN in a certain period of time, apply knowledge of basic concepts to solve qualitative problems. Find the North Star in the sky and navigate the terrain using the North Star and using a star map; find in the sky the main constellations and the brightest stars visible at this time of the year at a given time in a given area; use a mobile map of the starry sky, star atlases, reference books, the Astronomical calendar to determine the position and conditions for the visibility of celestial bodies and the course of celestial phenomena.
Equipment: PKZN, model of the celestial sphere. Astronomical calendar. Photo of the circumpolar region of the sky. Table for converting degrees to hours. CD- "Red Shift 5.1" (video clip = Excursions - Star Islands - Orientation in the sky).
During the classes:
- Repetition of the material (8-10 min).
1) Analysis of s / r from the last lesson (consider the task that caused difficulty).
2) Dictation.
- How many constellations are there in the sky? .
- How many stars can be counted with the naked eye in the sky? [about 6000].
- Write down the name of any constellation.
- What letter represents the brightest star? [α-alpha].
- Which constellation contains the North Star? [M. Medveditsa].
- What types of telescopes do you know? [reflector, refractor, mirror-lens].
- The purpose of the telescope. [increases the angle of view, gathers large lights].
- Name the types you know celestial bodies. [planets, satellites, comets, etc.].
- Name any star you know.
- Special scientific - research institution for observations. [observatory].
- What characterizes a star in the sky, depending on the apparent brightness. [magnitudes].
- A streak of light that crosses the sky and is visible on a bright starry night. [Milky Way].
- How to determine the direction to the north? [along the Polar Star].
- Decipher the entry Regulus (α Leo). [constellation Leo, star α, Regulus].
- Which star is brighter in the sky α or β? [α].
Estimated: “5” ≥ 14, “4” ≥ 11, “3” ≥8
II. New material (15 min).
BUT) Orientation in the skyCD- "Red Shift 5.1" (video clip = Excursions - Star Islands - Orientation in the sky), although this section could have been included in the 2nd lesson. |
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"Who knows how to find the North Star in the sky?". To find the North Star, you need to mentally draw a straight line through the stars of the Big Dipper (the first 2 stars of the "bucket") and count 5 distances between these stars along it. In this place, next to the straight line, we will see a star, almost the same in brightness with the stars of the "dipper" - this is the Polar Star (figure on the left). | Review of the starry sky on September 15, 21:00. Summer (summer-autumn) triangle = star Vega (a Lyra, 25.3 light years), star Deneb (a Cygnus, 3230 light years), star Altair (a Eagle, 16.8 light years). |
Photo of the circumpolar region of the sky. |
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1) A star is a light trail, a circle for a day | daily rotation of the sky - the position of the stars relative to each other does not change |
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The observed daily rotation of the celestial sphere (from east to west) is an apparent phenomenon that reflects the actual rotation the globe around its axis (west to east). // hint - daily rotation according to the movement of the Sun//. |
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In reality, the stars move in space and the distance to them is different. After all, if, for example, to estimate by eye the distance to the trees outside the window. Which one is closer to us? How much? And now we will mentally delete these two trees. Up to 500 m, a person confidently determines differences in distances to objects, and up to a maximum of 2 km. And at large distances, a person unconsciously uses other criteria - he compares the visible angular dimensions, relies on the perspective of the visible picture. Therefore, if the trees are in an open area where there is nothing else, then, starting from a certain distance, we will no longer distinguish which tree is closer (further) and, moreover, we will not be able to estimate the distance between them. It will seem to us from a certain moment that the treesequally distant from us. And in the sky, when the distance from the Earth to the Moon is 384,400 km, to the Sun - about 150 million km, and to the closest star, α Centauri, - 275,400 times more than to the Sun. Therefore, in the sky, it seems to us that all the luminaries are at the same distance. Human eyes, at best, can only distinguish distances within 2 km. |
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For solving many practical problems, distances to celestial bodies do not play a role, only their apparent location in the sky is important. Angular measurements are independent of the radius of the sphere. Therefore, although the celestial sphere does not exist in nature, astronomers use the concept of Celestial sphere – an imaginary sphere of arbitrary radius (arbitrarily large), in the center of which is the observer's eye. Stars, the Sun, the Moon, planets, etc. are projected onto such a sphere, abstracting from the actual distances to the luminaries and considering only the angular distances between them. The first mention of the "crystal spheres" by Plato (427-348, Ancient Greece). The first production of the celestial sphere was met by Archimedes (287-212, Ancient Greece), described in the work “On the production of the celestial sphere”. The most ancient celestial globe "Globe Farnese" 3rd c. BC e. from marble is kept in Naples. What is the center of the celestial sphere? (eye of the observer). What is the radius of the celestial sphere? (Arbitrary, but large enough). What is the difference between the celestial spheres of two neighbors on the desk? (Center position). |
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C) Celestial sphere and horizontal coordinate system |
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RR 1 - Peace Axis = axis of apparent rotation of the celestial sphere (parallel to the axis of rotation of the Earth). What is the rotation period of the celestial sphere? (Equal to the period of rotation of the Earth - 1 day). In what direction does the apparent (apparent) rotation of the celestial sphere take place? (Opposite to the direction of the Earth's rotation). What can be said about relative position axis of rotation of the celestial sphere and the earth's axis? (The axis of the celestial sphere and the earth's axis will coincide). Are all points of the celestial sphere involved in the apparent rotation of the celestial sphere? (Points lying on the axis are at rest). Where is the observer on this model? Where is the south and north poles of the world located on the globe? Where on the ball should the North Star be drawn? Specify the locus of points that do not change their location during rotation. In what direction does the apparent rotation of the celestial sphere occur when viewed from the north pole (from the south pole)? |
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The earth moves in an orbit around the sun. The axis of rotation of the Earth is inclined to the plane of the orbit at an angle of 66.5 ° (shown with a piece of cardboard pierced with a needle). Due to the action of gravitational forces from the side of the Moon and the Sun, the axis of rotation of the Earth is shifted, while the inclination of the axis to the plane of the Earth's orbit remains constant. The axis of the Earth, as it were, slides along the surface of the cone. (the same happens with the y-axis of an ordinary top at the end of rotation). This phenomenon was discovered as early as 125 BC. e. Greek astronomer Hipparchus and named precession . One rotation of the earth's axis takes 25,735 years - this period is calledplatonic year. Now near P - the north pole of the world is the Polar Star - α M. Medveditsa. Further, the title of Polar was alternately assigned to π, η and τ Hercules, the stars Tuban and Kokhab. The Romans did not have polar star, and Kokhab and Kinosuru (α Ursa Minor) were called Guardians. |
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Horizontal coordinate system |
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h - height - the angular distance of the star from the horizon (MOA, measured in degrees, minutes, seconds; from 0 o to 90 o ) A - azimuth - angular distance of the star's vertical from the south point (SOА)in the direction of the daily movement of the luminary, i.e. clockwise; measured in degrees minutes and seconds from 0 about to 360 about). |
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The horizontal coordinates of the star changes during the day. BUT" Equivalent altitude→zenith distance Z=90 o - h [form 1] |
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climax - the phenomenon of crossing the heavenly meridian by the luminary. |
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Luminary M during the day describes the daily parallel - a small circle of the celestial sphere, the plane of which is the axis of the world and passes through the eye of the observer. M 3 - sunrise point M 4 - entry point, M 1 - upper climax (h max; A= 0 o ), M 2 – lower climax (h min; A =180 o) According to the daily movement of the luminaries are divided into: 1 - non-ascending 2 - ( ascending - setting) ascending and descending 3 - non-approaching . What is the Sun, Moon? (2) |
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III Fixing the material(15 minutes). |
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A) Questions |
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B) practical work on PCZN. |
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C) 1. Translate 3 hours, 6 hours in degrees (3.
15=45
0
, 90
0
) |
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D) Test. For the phrase from the left column, choose the continuation from the right that is appropriate in meaning. |
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IV Summary of the lesson |
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1) Questions: |
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Homework:§ 3, p.19-questions. Page 30 (p. 7-9) |
The period of rotation of the Earth around its axis, measured relative to the stars and therefore called the sidereal (or sidereal) day, is about 4 minutes shorter than the mean solar day - the period of rotation of the Earth around its axis, measured relative to the Sun. This difference is due to the movement of the Earth around the Sun. Since the time by which we live, i.e. usual civil time, is associated with the average solar day, the moments of rising and setting of stars, measured at this time, are shifted every day by 4 minutes ahead compared to the previous day: the stars seem to slowly move across the night sky in a westerly direction. At times they come so close to the Sun that they become invisible - there comes a forced seasonal break in the observation of these objects.
Rice. 14. Scheme of a simple goniometric tool for measuring the height and azimuth of the star. Height is measured using a plumb line, azimuth is determined by the scale of the horizontal circle, which rotates with the vertical rack.
It is known that the stars really make their own movements in space, changing their position relative to each other. However, the stars are located so far from us that any changes in their position become visible to the naked eye after centuries. Thanks to this circumstance, we can talk about the movement of the Sun, Moon, planets and other celestial bodies relative to "fixed" stars. The great circle of the celestial sphere, along which the Sun makes its way among the stars during the year, is called the ecliptic. The plane of the ecliptic is inclined at an angle of 23.5° to the terrestrial and celestial equators; this is explained by the fact that the inclination of the Earth's axis of rotation to the ecliptic is 66.5°. It is for this reason that the height of the Sun above the horizon changes throughout the year and the seasons change. Paths of the Moon and major planets solar system pass within the region of the celestial sphere with a width of 8 °, lying on both sides of the ecliptic. Ancient observers singled out in a strip about 16 ° wide, stretching along the ecliptic, 12 zodiac constellations, to which astrologers attached special importance. After many centuries, due to precession, the position of the main points of the ecliptic among the surrounding stars has changed. The sun and planets may also appear in the constellation Ophiuchus (Ophiuchus); this constellation, which received its name in ancient times, is not included in the zodiac. Modern astronomers consider astrology and "star signs" nothing more than religious prejudices and superstitions. But the ancient signs of the Zodiac are still used to designate the zodiac constellations, for example, the sign of the constellation Aries (Aries) T denotes one of the two most important points in the celestial sphere at which the ecliptic crosses the celestial equator.
Translation celestial coordinates in terms of angle
Rice. 15. The poles of the world and the celestial equator are directly connected with the poles and the equator of the Earth. As the Earth rotates around its axis, all celestial bodies during the day cross the celestial meridian associated with the observer.
Rice. 16. The belt of the zodiac constellations, along which the planets and the Moon make their visible path, is stretched along the ecliptic - the apparent path of the Sun among the stars.
Gutenberg Library
Popular Science Series
"Amateur Astronomy"
For a more complete acquaintance with the sky, as well as for convenience, you can install a planetarium program on your computer, phone or tablet. For example, among novice astronomy enthusiasts, the free Stellarium planetarium is popular. This program allows you to simulate many phenomena and realistically show them. There are other virtual planetariums with a variety of functions and possibilities, and everyone can choose for themselves the one that meets their needs.
Optical instruments for astronomical observations
The time of ancient astronomers with goniometric instruments has long passed, and an astronomy lover, if he does not want to be limited to reading books, watching movies and searching for constellations on a map, needs an optical device.
If you have become interested in astronomy only recently and did not have experience of observations before, the best option for the first device for you will not be a large telescope, but binoculars. It is lighter and more compact than a telescope and is perfect for general viewing of the sky, milky way, bright nebulae and star clusters, large details on the surface of the moon. Comets can also be seen with binoculars.
When buying binoculars, pay attention primarily to its aperture (lens diameter) and magnification. For example, binoculars labeled 6x50 are binoculars with a 50mm aperture and 6x magnification. There are very large binoculars with high magnification, for example 20x100, but they cannot be used by hand due to their heavy weight and image trembling (trembling in the hands due to heavy binoculars is multiplied by high magnification). Therefore, such bulky instruments can only be used with a tripod. The optimal binocular parameters for sky surveys and handheld observations are 7x50 or 8x56.
Of course, a truly enthusiastic amateur is unlikely to limit himself to one pair of binoculars, and the telescope will naturally be the next step.
Amateur telescopes most often belong to the first two historical types - refractors and reflectors.
Refractors are easy to use due to the robust design of the tube and its tightness, do not often require adjustment and maintenance, give a contrast and clear image, which is important when observing the planets. But refractors also have disadvantages. Due to the fact that the light rays of different parts of the spectrum are refracted differently in glass, the image in them suffers from chromatic aberration, that is, it is colored at the edges in different colors(with the exception of expensive models, the so-called apochromats). In addition, models with large objective diameters are more expensive than similarly sized telescopes from other systems.
It is easier to make a mirror than a lens of the same diameter, so reflectors are on average cheaper than refractors. In addition, the mirror is lighter than the lens, which means that the weight of the telescope will be less. They are also free from chromatic aberration, since the rays in them are not refracted, but reflected. But reflectors also have disadvantages. The image in them is less contrast than in refractors, due to the loss of light when it is reflected on a small secondary mirror, which, moreover, does not let part of the light into the tube. The design of the pipe is not tight, which means that dust and dirt easily get inside. The mirror finish fades over time. Reflectors also have aberration, but of a different type - spherical (objects at the edges of the field of view look more blurred than in the center). In addition, the design of the reflector often requires adjustment (optics settings).
There are optical schemes that use both lenses and mirrors. Among amateurs, for example, the Schmidt-Cassegrain and Maksutov-Cassegrain systems are known, in which corrective lenses are installed in front of the mirror. They are free from many of the shortcomings of both refractors and reflectors, in addition, they have a short sealed tube that is convenient for transportation, but, as a rule, they are more expensive than both refractors and reflectors.
When choosing a telescope, you need, as in the case of binoculars, to clearly understand what you want from it, as well as what you can realistically expect from it. Not a single telescope, even a large one, will show you such pictures as in the photographs from the Hubble. Also, think about where you will be observing. If you live in a zone of intense illumination, then a bulky instrument with a large aperture, standing on the balcony, still will not show you all that it is capable of, and it will be difficult to transport it out of town, unlike a more compact telescope.
Read more:
Pozdnyakova, Irina. Amateur astronomy: people who discovered the sky / I. Yu. Pozdnyakova. - Moscow: AST Publishing House, 2018. - 334, p. : ill. - (Gutenberg Library).