The angular dimensions of the tail according to the coordinates of the stars are an example. Methods of visual observation of comets. A. Calculation of Meridian Time
Researcher in astronomy, Grade 11 for lesson No. 16 (workbook) - Small bodies of the Solar System
1. Complete the sentences.
Dwarf planets are a separate class of celestial objects.
Dwarf planets are objects that revolve around stars that are not satellites.
2. Dwarf planets are (underline as necessary): Pluto, Ceres, Charon, Vesta, Sedna.
3. Fill in the table: describe the distinctive features of the small bodies of the solar system.
| Specifications | Asteroids | Comets | Meteorites |
| View in the sky | Star-like object | Diffuse object | "Shooting star" |
| Orbits |
|
Short period comets P< 200 лет, долгого периода - P > 200 years; orbit shape - elongated ellipses | Varied |
| Average sizes | From tens of meters to hundreds of kilometers | Kernel - from 1 km to tens of km; tail ~ 100 million km; head ~ 100 thousand km | From micrometers to meters |
| Composition | Rocky | Ice with stone particles, organic molecules | Iron, stone, iron-stone |
| Origin | Collision of planetesimals | Remains of primary matter on the outskirts of the solar system | Shards from collisions, remnants of the evolution of comets |
| The consequences of a collision with the Earth | Explosion, crater | Air blast | Funnel on Earth, sometimes a meteorite |
4. Complete the sentences.
Option 1.
The remainder of the meteorite body, which did not burn out in the Earth’s atmosphere and fell to the surface of the Earth, is called a meteorite.
The size of the tail of comets can exceed millions of kilometers.
The comet's core consists of cosmic dust, ice and frozen volatile compounds.
Meteoric bodies burst into the Earth’s atmosphere at speeds of 7 km / s (burn out in the atmosphere) and 20-30 km / s (do not burn).
A radiant is a small part of the sky from which the visible paths of individual meteors of the meteor shower diverge.
Large asteroids have their own names, for example: Pallas, Juno, Vesta, Astrea, Hebe, Irida, Flora, Metida, Gigeya, Parthenopa, etc.
Option 2
A very bright meteor, visible on Earth as a ball of fire flying across the sky, is a car.
The heads of comets reach the size of the sun.
The tail of a comet consists of discharged gas and tiny particles.
Meteoric bodies flying into the Earth’s atmosphere shine, evaporate and burn completely at altitudes of 60-80 km, meteorite bodies larger in size can collide with the surface.
The solid fragments of the comet are gradually distributed in the comet’s orbit in the form of a cloud elongated along the orbit.
The orbits of most asteroids in the solar system are located between the orbits of Jupiter and Mars in the asteroid belt.
5. Is there a fundamental difference in the physical nature of small asteroids and large meteorites? Argument the answer.
An asteroid becomes a meteorite only when it enters the Earth’s atmosphere.
6. The figure shows a diagram of the meeting of the Earth with a meteor shower. Analyze the drawing and answer the questions.
What is the origin of the meteor shower (swarm of meteor particles)?
A meteorite stream is formed during the decay of cometary nuclei.
What determines the period of rotation of the meteor shower around the Sun?
From the period of revolution of the comet-ancestor, from the disturbance of the planets, the speed of ejection.
In which case will the largest number of meteors be observed on Earth (meteor shower or starry rain)?
When the Earth crosses the main mass of particles of a meteorite swarm.
By what principle are the names given to meteor showers? What are some of them?
By constellation, where the radiant is located.
7. Draw the structure of the comet. Indicate the following elements: core, head, tail.
8. * What energy will be released upon impact of a meteorite of mass m \u003d 50 kg, having a velocity near the surface of the Earth v \u003d 2 km / s?
9. What is the semimajor axis of the orbit of Halley's comet if its orbital period is T \u003d 76 years?
10. Calculate the approximate width of the Perseid meteor shower in kilometers, knowing that it is observed from July 16 to August 22.
“There is only one sure-fire way to determine the place and direction of a ship’s path to the sea - astronomical, and happy is the one who is familiar with it!”, With these words of Christopher Columbus we open a series of essays - lessons of astronavigation.
Maritime astronavigation originated in the era of great geographical discoveries, when “iron people sailed on wooden ships”, and for centuries has absorbed the experience of many generations of sailors. Over the past decades, it has been enriched with new measuring and computing means, new methods of solving navigation problems; recently appeared satellite navigation systems as they develop further will make all the difficulties of navigation a thing of the history. The role of marine astronavigation (from the Greek astro - star) remains extremely important today. The aim of our series of essays is to acquaint amateur navigators with modern astronomical orientation methods available in yachting conditions that are most often used on the high seas, but can also be applied in cases of coastal navigation when coastal landmarks are not visible or cannot be identified.
Observations of celestial landmarks (stars, the Sun, the Moon and planets) allow mariners to solve three main problems (Fig. 1):
- 1) measure time with sufficient accuracy for approximate orientation;
- 2) determine the direction of movement of the vessel even in the absence of a compass and the correction of the compass, if any;
- 3) determine the exact geographical location of the vessel and control the correctness of its path.
Depending on the applicable navigational instruments, manuals and computing tools, the accuracy of solving astronautical problems will be different. To be able to solve them in full and with sufficient accuracy for swimming on the high seas (the accuracy of the place is not more than 2-3 miles, in the compass correction - not more than 1 °), you must have:
- navigational sextant and a good waterproof watch (preferably electronic or quartz);
- a transistor radio for receiving time signals and a "Electronics" type calculator (this calculator must have a degree input of angles, provide direct and inverse trigonometric functions calculation, perform all arithmetic operations; the "BZ-34" is most convenient); in the absence of a calculator, you can use mathematical tables or special tables "Heights and azimuths of the stars" ("BAC-58") published by the Main Directorate of Navigation and Oceanography;
- marine Astronomical Yearbook (MAE) or other manual for calculating the coordinates of the stars.
In the absence of any of the astronavigation tools listed above, the very possibility of astronautical orientation remains, but its accuracy decreases (remaining, however, quite satisfactory for many cases of sailing). By the way, some tools and computing tools are so simple that they can be made independently.
Astronavigation is not only a science, but also an art - the art of observing luminaries in marine conditions and accurately performing calculations. Let the initial failures not disappoint you: a little patience and the necessary skills will appear, and with them will come a high satisfaction with the art of swimming beyond the sight of the coast.
All the methods of astronavigation that you will master are repeatedly tested in practice; they have already served the sailors more than once in the most critical situations. Do not postpone their development “for later”, master them in preparation for swimming; the success of the trip is decided on the shore!
Astronavigation, like all astronomy, is an observational science. Its laws and methods are derived from observations of the visible movement of the bodies, from the relationship between the geographic location of the observer and the visible directions to the bodies. Therefore, we will begin the study of astronavigation with observations of luminaries - we will learn to identify them; along the way, we will get acquainted with the principles of spherical astronomy we need in the future.
Heavenly landmarks
1. Navigation stars. At night, in a clear sky, we observe thousands of stars, however, in principle, each of them can be identified based on its location in the group of neighboring stars - its visible place in the constellation, its visible brilliance (brightness) and color.Only the brightest stars are used to navigate the sea, they are called navigation stars. Most often observed navigational stars are listed in table. 1; A complete catalog of navigational stars is available at MAE.
The picture of the starry sky is not the same in different geographical areas, at different seasons of the year and at different times of the day.
Starting an independent search for navigation stars in the northern hemisphere of the Earth, using a compass, determine the direction to the North point located on the horizon (indicated by the letter N in Fig. 2). Above this point, at an angular distance equal to the geographical latitude of your place φ, the Polar Star is located - the brightest among the stars of the constellation Ursa Minor, forming the shape of a bucket with a curved handle (Small Bucket). The polar one is designated with the Greek letter "alpha" and is called α Ursa Minor; For several centuries, it has been used by sailors as the main navigation reference. In the absence of a compass, the direction to the north is easily defined as the direction to the Polar.
As a scale for rough measurement of angular distances in the sky, you can apply the angle between the directions from your eye to the tips of the thumb and forefinger of an outstretched arm (Fig. 2); it's about 20 °.
The apparent brightness of the star is characterized by a conditional number, which is called the magnitude and is denoted by the letter m. The scale of magnitude has the form:
Shine m \u003d 0 is observed in summer, the brightest star of the northern starry sky - Vega (α Lyra). Stars of the first magnitude - with brilliance m \u003d 1 is 2.5 times weaker in brightness than Vega. Polar has a magnitude of about m \u003d 2; this means that its brightness is about 2.5 times weaker than that of stars of the first magnitude or 2.5 X 2.5 \u003d 6.25 times weaker than Vega’s brightness, etc. Only stars brighter can be observed with the naked eye m
Stellar magnitudes are given in table. 1; the color of the stars is also indicated there. It must, however, be borne in mind that color is perceived by people subjectively; in addition, as the horizon approaches, the brightness of the stars weakens noticeably, and their color shifts to the red side (due to the absorption of light in the earth's atmosphere). At an altitude of less than 5 °, most stars generally disappear from view.
The earthly atmosphere is observed by us in the form of the vault of heaven (Fig. 3), flattened above the head. In marine conditions, at night, the distance to the horizon seems to be about two times greater than the distance to the zenith point Z located above the head (from the Arabian zamt - top). During the day, the apparent flattening of the sky can increase one and a half to two times, depending on cloud cover and time of day.
Due to the very large distances to the celestial bodies, they seem to us equidistant and located in the sky. For the same reason, the relative position of stars in the sky changes very slowly - our starry sky is not much different from the starry sky of Ancient Greece. Only the celestial bodies closest to us - the Sun, planets, the Moon, noticeably move in the foyer of the constellations - figures formed by groups of mutually fixed stars.
Flattening of the sky leads to a distortion of the eye assessment of the apparent height of the body - the vertical angle h between the direction to the horizon and the direction to the body. These distortions are especially large at low altitudes. So, we note once again: the observed height of the star is always greater than its true height.
The direction to the observed luminary is determined by its true bearing of the SP — the angle in the horizontal plane between the direction to the North and the line of bearing of the luminary OD, which is obtained by the intersection of the vertical plane passing through the luminary and the horizontal plane. The luminaire’s IP is measured from the North point along an arc of the horizon towards the East point in the range 0 ° –360 °. The true bearing of the Polar is 0 ° with an error of not more than 2 °.
Having recognized the Polaris, find the constellation Ursa Major in the sky (see Fig. 2), which is sometimes called the Big Bucket: it is located at a distance of 30 ° -40 from the Polyarnaya, and all the stars of this constellation are navigation. If you have learned to confidently identify the Ursa Major, you can find the Polyarnaya without the help of a compass - it is located in the direction from the star Merak (see Table 1) at the star Dubge at a distance equal to 5 distances between these stars. Symmetrically to Ursa Major (relative to Polar), the constellation Cassiopeia is located with the navigation stars Kaff (β) and Shedar (α). In the seas washing the shores of the USSR, all the constellations we mentioned are visible at night over the horizon.
Having found Ursa Major and Cassiopeia, it is not difficult to identify other constellations and navigation stars located near them, if you use the map of the starry sky (see Fig. 5). It is useful to know that the arc in the sky between the stars of Dubge and Bevetnash is approximately 25 °, and between the stars β and ε of Cassiopeia - about 15 °; these arcs can also be used as a scale for the approximate estimation of angular distances in the sky.
As a result of the Earth's rotation around its axis, we see the rotation of the sky visible to us towards the West around the direction to the Polar; every hour the starry sky turns by 1 h \u003d 15 °, every minute by 1 m \u003d 15 ", and during the day by 24 hours \u003d 360 °.
2. The annual movement of the Sun in the sky and seasonal changes in the appearance of the starry sky. During the year, the Earth makes in outer space one full revolution around the Sun. The direction from the moving Earth to the Sun for this reason is constantly changing; The sun describes the dashed curve shown on the star map (see tab), which is called the ecliptic.
The visible place of the Sun makes the ecliptic its own annual motion in the direction opposite to the apparent diurnal rotation of the starry sky. The speed of this annual movement is small and equal to I / day (or 4 m / day). In different months, the Sun passes through various constellations that form the zodiacal belt (“circle of animals”) in the sky. So, in March, the Sun is observed in the constellation Pisces, and then sequentially in the constellations Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius.
Constellations located on the same hemisphere with the Sun are illuminated by it and are not visible during the day. At midnight in the south, constellations are visible, 180 ° \u003d 12 hours from the place of the Sun on this calendar date.
The combination of the fast visible diurnal motion of stars and the slow annual motion of the Sun leads to the fact that the currently observed picture of the starry sky tomorrow will be visible 4 m earlier, after 15 days - by
earlier, in a month - 2 hours earlier, etc.
3. The geographical and visible place of the star. Map of the starry sky. Star globe. Our Earth has a spherical shape; now this is clearly proved by her images taken by space stations.
In navigation, it is believed that the Earth has the shape of a regular ball, on the surface of which two geographic coordinates determine the place of the yacht:
Geographic latitude φ (Fig. 4) - the angle between the plane of the earth's equator eq and the direction of the plumb line (the direction of gravity) at the observation point O. This angle is measured by the arc of the geographic meridian of the observer’s place (briefly, the local meridian) eO from the equatorial plane to the side of the Earth’s pole closest to the observation site within 0 ° -90 °. Latitude can be north (positive) or south (negative). In fig. 4, the latitude of the O place is equal to φ \u003d 43 ° N. The latitude determines the position of the geographical parallel - a small circle parallel to the equator.
Geographic longitude λ is the angle between the planes of the initial geographical meridian (according to international agreement, it passes through the Greenwich Observatory in England - G in Fig. 4) and the plane of the local meridian of the observer. This angle is measured by the arc of the earth's equator e gr e towards the East (or West) within 0 ° -180 °. In fig. 4 the longitude of the place is λ \u003d 70 ° O st. Longitude determines the position of the local meridian.
The direction of the local meridian at the O observation point is determined by the direction of the sun’s shadow at noon from the vertical pole; at noon this shadow has the shortest length, on a horizontal platform it forms the midday line N-S (see Fig. 3). Any local meridian passes through the geographic poles P n and P s, and its plane passes through the axis of rotation of the Earth P n P s and the vertical line OZ.
A ray of light from a distant star * arrives at the center of the Earth in the direction * Ts, crossing the earth's surface at some point σ. Imagine that an auxiliary sphere (celestial sphere) is described from the center of the Earth with an arbitrary radius. The same ray will cross the celestial sphere at the point σ ". The point σ is called the geographic place of the star (HMS), and the point σ" is the visible place of the star on the sphere. According to fig. 4. it can be seen that the position of the HMS is determined by the geographical sprat φ * and the geographical longitude λ *.
Similarly, the position of the visible place of the star in the celestial sphere is determined:
- the arc of the HMS meridian φ * is equal to the arc δ of the celestial meridian passing through the visible place of the star; this coordinate on the sphere is called the declination of the luminary; it is measured in the same way as latitude;
- the arc of the earth's equator λ * is equal to the arc t gr of the celestial equator; on a sphere, this coordinate is called the Greenwich hour angle, it is measured in the same way as longitude, or, in a circular count, always towards the West, in the range from 0 ° to 360 °.
The position of the meridian of the visible place of the star in the celestial sphere can be determined not only with respect to the celestial Greenwich meridian. Let us take as the reference point the point of the celestial equator at which the Sun is visible on March 21. On this day, spring begins for the northern hemisphere of the Earth; day is equal to night; the mentioned point is called the Spring point (or Aries point) and is indicated by the Aries sign - ♈, as shown on the star map.
The equatorial arc from the point of Spring to the meridian of the visible place of the body, counted towards the visible daily movement of the bodies from 0 ° to 360 °, is called the stellar angle (or stellar complement) and is denoted by τ *.
The equatorial arc from the point of Spring to the meridian of the visible place of the star, counted in the direction of the Sun's own annual movement in the celestial sphere, is called the right ascension α (in Fig. 5 it is given in a clockwise measure, and the stellar angle is in degree measure). The coordinates of the navigation stars are shown in table. 1; obviously, knowing τ °, one can always find
and vice versa.
The arc of the celestial equator from the local meridian (its midday part P n ZEP s) to the meridian of the luminary is called the local hourly angle of the luminaries denoted by t. According to fig. 4 it is seen that always t differs from t gr by the magnitude of the longitude of the observer's place:
while eastern longitude is added, and western - is subtracted if t gr is taken in a circular account.
Due to the visible diurnal movement of the luminaries, their hourly angles are constantly changing. The stellar angles for this reason do not change, since the origin (spring point) rotates together with the firmament.
The local hourly point of Spring is called sidereal time; it is always measured towards the West from 0 ° to 360 °. Glazomerno it can be determined by the position in the sky of the meridian of the star Kaff (β Cassiopeia) relative to the local celestial meridian. According to fig. 5 shows that always
Practice eye-level determination of the equatorial coordinates δ and t of the stars you observe in the sky. To do this, determine the position of the North point on the horizon using Polar (Fig. 2 and 3), then find the South point. Calculate the complement of the latitude of your place Θ \u003d 90 ° - φ (for example, in Odessa Θ \u003d 44 °, and in Leningrad Θ \u003d 30 °). The midday point of the equator E is located above the South point at an angular distance equal to Θ; it is always the origin of the hour angle. The equator in the sky passes through the point of the East, point E and the point of the West.
It is useful to know that at δ N\u003e 90 ° - φ N, the star in the northern hemisphere of the Earth always moves above the horizon, at δ 90 ° - φ N it is not observed.
The mechanical model of the celestial sphere, reproducing the appearance of the starry sky and all the coordinates considered above, is the stellar globe (Fig. 6). This navigation device is very useful in long-distance navigation: with it you can solve all the problems of astronautical orientation (with an angular error of the solution results of not more than 1.5-2 ° or with an error in time of not more than 6-8 minutes. Before operation, the globe is set in latitude the places of observations (shown in Fig. 6) and local stellar time t γ.The rules for calculating which for the period of observations will be explained below.
If desired, a simplified stellar globe can be made from a school globe, if you put the visible places of stars on its surface, guided by the table. I and a map of the starry sky. The accuracy of solving problems on such a globe will be somewhat lower, but sufficient for many cases of orientation in the direction of movement of the yacht. We also note that the star map gives a direct image of the constellations (as the observer sees them), and their inverse images are visible on the star globe.
Star recognition
Of the countless stars with the naked eye, only about 600 are easily observed, shown on a map of the starry sky in the Sea Astronomical Yearbook. This map gives a generalized picture of what a sailor can generally observe in a dark night sky. To answer the question of where and how to search for certain navigational stars in a certain geographical area, seasonal patterns of the starry sky given below (Fig. 1-4) are used: they cover the view of the starry sky for all the seas of the country and are based on the MAE star map ; they indicate the position and proper names of all 40 navigational stars mentioned in the table in the previous essay.Each pattern corresponds to evening observations at a certain time of the year: in spring (Fig. 1), in summer (Fig. 2), in autumn (Fig. 3), and in winter (Fig. 4), or to morning observations in spring (Fig. 2), in summer (Fig. 3), in autumn (Fig. 4) and in winter (Fig. 1). Each seasonal pattern can be used at a different time of the year, but at a different time of the day.
To select a seasonal pattern suitable for the intended observation time, use the table. 1. Enter this table by the closest to the scheduled calendar date of observations and the so-called "meridian" time of day T M.
Meridian time with an allowable error of no more than half an hour can simply be obtained by reducing the winter time adopted in the USSR since 1981 by 1 hour, and summer time by 2 hours. The rules for calculating T marine conditions according to the ship time adopted on board the yacht are explained in the example below. The bottom two rows of the table for each seasonal pattern indicate the corresponding stellar time t M and the reference of the stellar angle τ K according to the scales of the star map MAE; These values \u200b\u200ballow you to determine which of the meridians of the star map at the intended time of observation coincides with the meridian of your geographical location.
At the initial development of the rules for identifying navigation stars, it is necessary to prepare for observations in advance; used and a map of the starry sky, and a seasonal pattern. Orient the star map on the ground; from the south point on the horizon in the direction of the north pole of the world will be located the meridian of the equatorial star map, which is digitized by the value of t M, i.e. for our seasonal patterns - 12 H, 18 H, 0 (24) H and 6 H. This Meridian and shown by a dotted line on seasonal diagrams. The half-width of each of the schemes is approximately 90 ° \u003d 6 H; therefore, after hours, due to the rotation of the starry sky to the west, the dotted meridian will shift to the left edge of the diagram, and its central constellations to the right.
The equatorial map covers the starry sky between the parallels 60 ° N and 60 ° S, but not all the stars shown on it will necessarily be visible in your area. Above the head, near the zenith, those constellations are visible in which the declination of the stars is close in magnitude to the latitude of the place (and is "of the same name" with it). For example, in the latitude φ \u003d 60 ° N at t М \u003d 12 H, the constellation Ursa Major is located above the head. Further, as was already explained in the first essay, it can be argued that at φ \u003d 60 ° N, stars located south of the parallel with a declination of δ \u003d 30 ° S will never be visible, etc.
For an observer in northern geographical latitudes, the equatorial star map shows mainly those constellations that are observed in the southern half of the sky. To determine the visibility of the constellations in the northern half of the sky, use the northern polar map, covering the area outlined from the north pole of the world with a radius of 60 °. In other words, the northern polar map overlaps the equatorial map in a wide belt between the parallels of 30 ° N and 60 ° N. To orient the polar map in the area, you need its meridian, digitized from the table. 1 value τ, position above the head so that it coincides with the direction from the zenith to the north pole of the world.
The field of view of the human eye is approximately equal to 120-150 °, so if you look at the Polar one, then all the constellations of the northern polar map will be in the field of view. Those northern constellations whose stars have declination δ\u003e 90 ° - φ and " of the same name ”with latitude. For example, at latitude φ \u003d 45 ° N, stars with declination greater than δ \u003d 45 ° N are non-descending, and at latitude φ \u003d 60 ° N those stars with δ\u003e 30 ° N., etc.
Recall that all the stars in the sky have the same size - they are visible as luminous dots and differ only in brightness and color. The size of the circles on the star map does not indicate the apparent size of the star in the sky, but the relative strength of its brightness - magnitude. In addition, the image of the constellation is always somewhat distorted when the surface of the celestial sphere is deployed on the plane of the map. For these reasons, the view of the constellation in the sky is somewhat different from the view on the map, however, this does not create significant difficulties in identifying stars.
Learning to identify navigation stars is not difficult. For swimming during your vacation, it is enough to know the location of a dozen constellations and the navigation stars included in them from the number indicated in the table. 1 first essay. Two to three pre-night night workouts will give you confidence when navigating the stars in the sea.
Do not try to identify the constellations by looking for figures of mythical heroes or animals that correspond to their alluring sounding names. Of course, one can guess that the constellations of the northern animals - Ursa Major and Ursa Minor should most often be sought in the north direction, and the constellation of the southerner Scorpio - in the southern half of the sky. However, in fact, the observed species of the same northern constellations - the "Bears" is better conveyed by famous verses:
Two bears laugh:
“Did these stars cheat on you?”
They are called by our name
And they look like pots.
When identifying stars, Ursa Major is more convenient to call the Big Dipper, which we will do. Those wishing to find out details about the constellations and their names are sent to the excellent “starter ABC book” G. Ray and an interesting book by Yu. A. Karpenko.
For the navigator, a practical guide to the starry sky can serve as diagrams - indexes of navigational stars (Fig. 1-4), showing the location of these stars relatively easily identifiable from star charts of several reference constellations.
The main reference constellation is Ursa Major, whose bucket in our seas is always visible above the horizon (with a latitude of more than 40 ° N) and is easily recognizable even without a map. Let us remember the proper names of the stars of the Big Bucket (Fig. 1): α - Dubge, β - Merak, γ - Fekda, δ - Meghrets, ε - Aliot, ζ - Mitsar, η - Benetnash. You already know the seven nautical stars!
In the direction of the Merak – Dubge line, a distance of about 30 ° is located, as we already know, the Polyarnaya is the end of the handle of the Ursa Minor bucket, in the bottom of which Kokhab is visible.
On the Megrets - Polyarnaya line and at the same distance from the Polar one you can see the “girl’s chest” of Cassiopeia and its stars Kuff and Shedar.
In the direction of Fekda - Megrets and at a distance of about 30 ° we find the star Deneb, located at the tail of the constellation Cygnus - one of the few, at least to some extent corresponding in configuration to its name.
In the direction of Fekda - Aliot, in the region approximately 60 ° distant, the brightest northern star is visible - the blue beauty Vega (and Lyra).
In the direction of Mitsar - Polyarnaya and at a distance of about 50 ° -60 ° from the pole, the Andromeda constellation is located - a chain of three stars: Alferraz, Mirah, Alamak of the same brightness.
In the direction Mirah - Alamak, Mirfak (α Perseus) is also visible at the same distance.
In the direction Megrets - Dubge at a distance of about 50 °, a pentagonal cup of the Ascendant is visible and one of the brightest stars is the Chapel.
In this way we found almost all the navigational stars visible in the northern half of our firmament. Using rice. 1, it is worth practicing in search of nautical stars first on star charts. When training "on the ground", keep rice. 1 “upside down”, pointing the * to point N.
We turn to the consideration of navigation stars in the southern half of the spring firmament in the same fig. 1.
Perpendicular to the bottom of the Big Bucket at a distance of about 50 ° is the constellation Leo, in the front leg of which Regulus is located, and at the tip of the tail - Denebol. To some observers, this constellation does not resemble a lion, but an iron with a bent handle. In the direction of the tail of Leo, the constellation Virgo and the star of Spica are located. To the south of the Leo constellation in a region poor in stars near the equator, a dim Alphard (and Hydra) will be noticeable.
On the Megrez - Merak line at a distance of about 50 °, the constellation Gemini is visible - two bright stars Castor and Pollux. On the same meridian with them and closer to the equator is a bright Procyon (α Small Dog).
Moving our eyes along the bend of the handle of the Big Bucket, at a distance of about 30 ° we will see a bright orange Arcturus (α Bootes - a constellation resembling a parachute over Arcturus). Next to this parachute is a small and dim cup of the Northern Crown, in which Alfacca stands out,
Continuing the direction of the same bend of the handle of the Big Bucket, not far from the horizon we will find Antares - the bright reddish eye of the constellation Scorpio.
On a summer evening (Fig. 2), on the eastern side of the sky, the “summer triangle” is clearly visible, formed by the bright stars Vega, Deneb and Altair (α Orla). The Eagle constellation in the form of a rhombus is easily found in the direction of Swan's flight. Between Orel and Bootes there is a dim star Ras Alhage from the constellation Ophiuchus.
In autumn evenings, the Pegasus Square is observed in the south, formed by the Alferraz star we have already examined and three stars from the Pegasus constellation: Markab, Sheat, Algenib. Pegasus Square (Fig. 3) is easily found on the Polyarnaya - Kaff line at a distance of about 50 ° from Cassiopeia. Regarding Pegasus Square, it’s easy to find the constellations of Andromeda, Perseus and the Charioteer to the east, and the constellations of the “summer triangle” to the west.
South of Pegasus Square near the horizon, Difda (β Whale) and Fomalhout, the “mouth of the Southern Fish”, which Whale intends to swallow, are visible.
On the Markab - Algeinb line, at a distance of about 60 °, a bright Aldebaran (α Taurus) is visible in the characteristic "splashes" of small stars. Between the constellations of Pegasus and Taurus is Hamal (α Aries).
In the southern half of the winter sky, rich in bright stars (Fig. 4), it is easy to navigate with respect to the most beautiful constellation of Orion, which is recognized without a map. The constellation of the charioteer is located in the middle between Orion and the Polar. The constellation Taurus is located on the continuation of the arc of the Orion belt (formed by the “three sisters” stars ζ, ε, δ of Orion) at a distance of about 20 °. On the southern extension of the same arc at a distance of about 15 ° the brightest star sparkles - Sirius (α Canis Major). In the direction γ - α of Orion, Portion is observed at a distance of 20 °.
In the constellation Orion, the navigation stars are Betelgeuse and Rigel.
It should be borne in mind that the appearance of the constellations can be distorted by the planets appearing in them - “wandering stars”. The position of the planets in the starry sky in 1982 is indicated in the table. 2 So, having studied this table, we will establish that, for example, in May Venus will not be visible in the evening, Mars and Saturn will distort the view of the Virgo constellation, and not far from them in the constellation Libra will be visible very bright Jupiter (rarely observed “planetary parade” ) Information about the visible places of the planets is given for each year in the MAE and the Astronomical Calendar of the Nauka Publishing House. They must be applied to the star map in preparation for the trip, using the direct ascents and inclinations of the planets indicated in these manuals on the date of observation.
The seasonal patterns given are indicators of nautical stars (Fig. 1-4), which are most convenient for working at dusk, when the horizon and only the brightest stars are clearly visible. The constellation configurations depicted on starry sky maps can only be detected after complete darkness.
The search for navigational stars should be meaningful, the form of the constellation must be learned to perceive as a whole - as an image, a picture. A person quickly and easily recognizes what he intends to see. That is why, in preparation for swimming, you need to study the star map in the same way as a tourist studies the route of a walk through an unfamiliar city on a map.
Leaving for observation, take with you a star map and a pointer to the navigational stars, as well as a pocket lamp (it is better to cover its glass with red nail polish). The compass will be useful, but you can do without it, having determined the direction to the North along the Polar. Think about what will serve as a “scale ruler” for estimating angular distances in the sky. In the angle under which an object held in an outstretched hand and perpendicular to it is visible, there are as many degrees as centimeters this object has in height. In the sky, the distance between the stars of Dubge and Megrets is 10 °, between the stars of Dubge and Benetnash - 25 °, between the extreme stars of Cassiopeia - 15 °, the eastern side of Pegasus Square - 15 °, between Rigel and Betelgeuse - about 20 °.
Having left the area at the appointed time - navigate to the directions to the North, East, South and West. Find I recognize the constellation passing above your head - through or near the zenith. Make a reference to the terrain of the seasonal pattern and the equatorial map - at point S and the direction of the local celestial meridian, perpendicular to the horizon at point S; tie the northern polar map to the area - along the ZP line. Find the constellation Ursa Major (Pegasus Square or Orion) and practice identifying nautical stars. In this case, one must remember the distortions of the magnitudes of the visually observed luminosities due to the flattened sky, the color distortions of stars at low altitudes, the apparent increase in the size of the constellations near the horizon, and decrease as they approach the zenith, and the change in the position of the figures of the constellations during the night relative to the visible horizon from due to the rotation of the sky.
A. Calculation of Meridian Time
B. An example of calculating the meridian time and choosing a seasonal pattern of the starry sky
On May 8, 1982, in the Baltic Sea (latitude φ \u003d 59.5 ° N; longitude λ \u003d 24.8 ° O st, observations of the starry sky at time T C \u003d 00 × 30 M according to standard (summer Moscow) time are planned. Orient the star map and the index of navigation stars.On the shore, you can approximately take T M equal to summer, reduced by 2 hours. In our example:
In all cases when the standard observation time T C is less than No. C, before performing the subtraction, it is necessary to increase T C by 24 H; at the same time, the world date will be less than the local one. If it turns out that after completing the addition of T gr, it turned out to be more than 24 hours, you need to drop 24 hours and increase the date of the result by one. The same rule applies when calculating T M from G gr and λ.
Choice of seasonal pattern and its orientation
The local date of May 7 and the moment T M \u003d 22 H 09 M according to the table. 1 closest corresponds to the seasonal pattern in Fig. 1. But this scheme was built for T M \u003d 21 H on May 7, and we will conduct observations 1 H 09 M later (in degree measure 69 M: 4 M \u003d 17 °). Therefore, the local meridian (line S - P N) will be located 17 ° to the left of the central meridian of the scheme (if we had observed not later, but earlier, the local meridian would have shifted to the right).
In our example, the Virgo constellation above the South point and the Ursa Major constellation near the zenith will pass through the local meridian, and Cassiopeia will be located at the North point (see star map for tγ \u003d 13 × 09 M and τ К \u003d 163 °).
An orientation relative to the Ursa Major will serve to identify navigation stars (Fig. 1).
Notes
1. The faint constellations of Pisces and Cancer are not shown on the map.2. The names of these books. G. Ray. Stars. M., Mir, 1969. (168 p.); Yu. A, Karpenko, Names of the starry sky, M., “Science”, 1981 (183 p.).
Nodal issues: 1. The concept of constellation. 2. The difference of stars in brightness (luminosity), color. 3. The magnitude. 4. Visible diurnal movement of stars. 5. celestial sphere, its main points, lines, planes. 6. Star map. 7. Equatorial SC.
Demonstrations and TCO: 1. Demonstration moving map of the sky. 2. The model of the celestial sphere. 3. Star atlas. 4. Transparencies, photographs of the constellations. 5. The model of the celestial sphere, geographical and stellar globes.
For the first time, stars were indicated by the letters of the Greek alphabet. In the constellation of the atlas of Bayger in the XVIII century, the drawings of the constellations disappeared. The magnitude is indicated on the map.
Ursa Major - (Dubhe), (Merak), (Fekda), (Megrets), (Aliot), (Mizar), (Benetash).
Lyra - Vega, Lebedeva - Deneb, Bootes - Arcturus, Voznichy - Capella, B. Dog - Sirius.
The sun, moon and planets are not indicated on the maps. The path of the Sun is shown on the ecliptic by Roman numerals. On star maps, a grid of celestial coordinates is plotted. The observed daily rotation is an apparent phenomenon - caused by the actual rotation of the Earth from west to east.
Earth rotation proof:
1) 1851 physicist Foucault - Foucault pendulum - length 67 m.
2) space satellites, photographs.
Celestial sphere - an imaginary sphere of arbitrary radius used in astronomy to describe the relative position of the stars in the sky. The radius is taken as 1 pc.
88 constellations, 12 zodiacal. It can be conditionally divided into:
1) summer - Lira, Swan, Eagle 2) autumn - Pegasus with Andromeda, Cassiopeia 3) winter - Orion, B. Dog, M. Dog 4) spring - Virgo, Bootes, Leo.
Plumb line crosses the surface of the celestial sphere at two points: at the top Z - zenith - and at the bottom Z" - nadir.
Mathematical horizon - a large circle on the celestial sphere, the plane of which is perpendicular to the vertical line.
Point N the mathematical horizon is called north point, point S - south point. Line NS - called midday line.
Heavenly equator called the big circle perpendicular to the axis of the world. The celestial equator intersects with the mathematical horizon in points east E and the west W.
Heavenly meridian called the great circle of the celestial sphere passing through the zenith Z, the pole of the world R, south pole of the world R", nadir Z".
Homework: § 2.
Constellations. Star cards. Heavenly coordinates.
1. Describe what diurnal circles stars would describe if astronomical observations were carried out: at the North Pole; at the equator.
The visible movement of all stars occurs in a circle parallel to the horizon. The North Pole of the world when viewed from the North Pole of the Earth is at its zenith.
All stars ascend at right angles to the horizon in the eastern part of the sky and also go beyond the horizon in the western. The celestial sphere rotates around an axis passing through the poles of the world, at the equator located exactly on the horizon.
2. Express 10 h 25 min 16 s in a degree measure.
Earth in 24 hours makes one revolution - 360 about. Therefore, 360 о corresponds to 24 hours, then 15 о - 1 hour, 1 о - 4 min, 15 / - 1 min, 15 // - 1 s. Thus,
1015 о + 2515 / + 1615 // \u003d 150 о + 375 / +240 / \u003d 150 о + 6 о +15 / +4 / \u003d 156 о 19 /.
3. Determine the equatorial coordinates of Vega from the star map.
Replace the name of the star with the letter designation (Lyra) and find its position on the star map. We draw a circle of declination through an imaginary point to the intersection with the celestial equator. The arc of the celestial equator, which lies between the vernal equinox and the intersection point of the declination circle of the star with the celestial equator, is a direct ascent of this star, counted along the celestial equator to meet the apparent diurnal rotation of the celestial sphere. The angular distance measured in the circle of declination from the celestial equator to the star corresponds to declination. Thus, \u003d 18 h 35 m, \u003d 38 about.
We rotate the overlay circle of the star map so that the stars cross the eastern part of the horizon. On the limb, opposite the mark of December 22, we find the local time of its sunrise. Positioning the star in the western part of the horizon, we determine the local time of sunset of the star. We get
5. Determine the date of the upper culmination of the star Regulus at 21 hours local time.
Set the invoice circle so that the star Regulus (Leo) is on the line of the celestial meridian (0 h - 12 h overhead circle) south of the north pole. On the limb of the overlay circle we find the mark 21 and opposite it on the edge of the overlay circle we determine the date - April 10.
6. Calculate how many times Sirius is brighter than the North Star.
It is generally accepted that, with a difference of one magnitude, the apparent brightness of stars differs by approximately 2.512 times. Then a difference of 5 magnitudes will make a difference in brightness exactly 100 times. So stars of the 1st magnitude are 100 times brighter than stars of the 6th magnitude. Consequently, the difference in the visible magnitude of the two sources is equal to unity when one of them is brighter than the other in (this value is approximately equal to 2.512). In the general case, the ratio of the apparent brightness of two stars is associated with the difference in their visible magnitudes with a simple ratio:
Luminaries whose brightness exceeds the brightness of stars 1 m , have zero and negative magnitudes.
Stellar magnitudes of Sirius m 1 \u003d -1.6 and the North Star m 2 \u003d 2.1, we find in the table.
Prologarithm both parts of the above ratio:
Thus, . From here. That is, Sirius is 30 times brighter than the North Star.
Note: using a power function, we also get the answer to the question of the problem.
7. Do you think it is possible to fly on a rocket to any constellation?
A constellation is a conditionally defined part of the sky, within which there are luminaries located at different distances from us. Therefore, the expression "fly to the constellation" is meaningless.
HOW TO OBSERVE COMETS
Vitaly Nevsky
Watching comets is a very exciting experience. If you have not tried your hand at this, I highly recommend trying. The fact is that comets are very volatile objects by nature. Their appearance can vary from night to night and very significantly, especially for bright comets visible with a simple eye. Such comets, as a rule, develop decent tails, prompting their ancestors to various prejudices. Such comets do not need advertising, this is always an event in the astronomical world, but rather rare, but weak telescopic comets are almost always available for observation. I also note that the results of observations of comets are of scientific value, and observations of amateurs are constantly published in the American journal Internatoinal Comet Quarterly, on the website of C. Morris and not only.
First, I’ll tell you what to look for when observing a comet. One of the most important characteristics is the magnitude of the comet; it must be estimated using one of the methods described below. Then comes the diameter of the comet's coma, the degree of condensation, and in the presence of the tail, its length and position angle. These are the data that are of value to science.
Moreover, in the comments on the observations, it should be noted whether the photometric core was observed (do not confuse with the true core, which cannot be seen through the telescope) and how it looked: star-shaped or in the form of a disk, bright or weak. For bright comets, such phenomena as galosies, shells, separation of tails and plasma formations, the presence of several tails at once are possible. In addition, more than fifty comets have already seen nuclear decay! Let me explain these phenomena a little.
- Halos are concentric arcs around the photometric core. They were clearly visible in the famous comet Hale-Bopp. These are dust clouds regularly ejected from the nucleus, gradually moving away from it and disappearing against the background of the comet's atmosphere. They must be sketched indicating the angular dimensions and time of the sketch.
- Decay of the nucleus. The phenomenon is quite rare, but has already been observed in more than 50 comets. The onset of decay can be seen only at maximum magnifications, which should be reported immediately. But you need to be careful not to confuse the decay of the nucleus with the separation of the plasma cloud, which happens more often. The decay of the nucleus is usually accompanied by a sharp increase in the brightness of the comet.
- Shells - appear on the periphery of the cometary atmosphere (see. Fig.), Then begin to shrink, as if collapsing on the nucleus. When observing this phenomenon, it is necessary to measure the vertex height (V) in angular minutes — the distance from the core to the top of the shell and the diameter P \u003d P1 + P2 (P1 and P2 may not be equal). These estimates must be done several times during the night.
Comet Gloss Rating
The accuracy of the estimate should not be lower than +/- 0.2 magnitude. In order to achieve similar accuracy, the observer in the course of work for 5 min should make several brightness estimates, preferably for different comparison stars, finding the average value of the magnitude of the comet. In this way, the obtained value can be considered quite accurate, but not the one obtained as a result of only one assessment! In such a case, when the accuracy does not exceed +/- 0.3, a colon (:) is put after the magnitude of the comet. If the observer could not find the comet, then he estimates the limiting magnitude for his instrument on this night, at which he could still observe the comet. In this case, the left bracket ([) is placed before the evaluation.
The literature provides several methods for estimating the stellar magnitude of a comet. But the most applicable are the method of Bobrovnikov, Morris and Sidgvik.
Bobrovnikov's method.
This method is used only for comets, the degree of condensation of which is in the range of 7-9! Its principle is to bring the telescope’s eyepiece out of focus until the extrafocal images of the comet and comparison stars are approximately the same diameter. It is impossible to achieve full equality, since the diameter of the image of a comet is always larger than the diameter of the image of a star. It should be borne in mind that in an out-of-focus image of a star, the brightness is approximately the same, and the comet looks like a spot of uneven brightness. The observer must learn to average the brightness of the comet over its entire out-of-focus image and compare this average brightness with comparison stars. Comparison of the brightness of off-focal images of a comet and comparison stars can be performed using the Neyland-Blazhko method.
Sidgwick Method.
This method is used only for comets, the degree of condensation of which is in the range of 0-3! Its principle is to compare the focal image of a comet with off-focal images of comparison stars, which, when defocused, have the same diameters as the focal comet. The observer first carefully examines the image of the comet, "recording" its brightness in memory. Then it defocuses the comparison stars and evaluates the comet’s brilliance recorded in memory. A certain skill is needed here in order to learn how to evaluate the brilliance of a comet recorded in memory.
Morris Method.
The method combines the features of the methods of Bobrovnikov and Sidgvik. it can be used for comets with any degree of condensation! The principle boils down to the following sequence of techniques: an off-focal image of a comet is obtained that has approximately uniform surface brightness; remember the size and surface brightness of the extrafocal image of the comet; defocus the images of comparison stars so that their sizes are equal to the sizes of the remembered image of the comet; evaluate the brightness of the comet by comparing the surface brightness of the off-focal images of the comet and comparison stars.
When evaluating the brightness of comets, in the case when the comet and comparison stars are at different heights above the horizon, a correction for atmospheric absorption must be introduced! This is especially significant when the comet is below 45 degrees above the horizon. Corrections should be taken from the table and the results must indicate whether the amendment was introduced or not. When using an amendment, you need to be careful not to make a mistake, whether it should be added or subtracted. Suppose a comet is below the comparison stars, in which case the correction is subtracted from the brightness of the comet; if the comet is higher than the comparison stars, then the correction is added.
To assess the brightness of comets, special stellar standards are used. Not all atlases and catalogs can be used for this purpose. Of the most accessible and widespread at present, the catalogs of Tycho2 and Draper should be highlighted. For example, directories such as AAVSO or SAO are not recommended. You can see more about this.
If you do not have recommended directories, they can be downloaded from the Internet. A great tool for this is Cartes du Ciel.
Comet Diameter
The diameter of the comet's coma should be estimated using the smallest increase possible! It is noted that the smaller the magnification is applied, the larger the diameter of the coma, since the contrast of the comet's atmosphere with respect to the sky background increases. The poor transparency of the atmosphere and the light background of the sky (especially with the moon and urban exposure) strongly affect the estimation of the diameter of the comet, so in such conditions it is necessary to be very careful when measuring.
There are several methods for determining the diameter of a comet's coma:
- With a micrometer, which is easy to do yourself. Under a microscope, pull thin filaments at certain intervals in the diaphragm of the eyepiece, and it is better to use an industrial one. This is the most accurate method.
- The drift method. It is based on the fact that with a stationary telescope, the comet, due to the diurnal rotation of the celestial sphere, will slowly cross the field of view of the eyepiece, passing for 1sec a 15 "arc near the equator. Using an eyepiece with a cross of strings pulled in it, rotate it so that the comet moves along one thread and, therefore, perpendicular to another thread of the cross. Having determined by the stopwatch the time interval in seconds for which the comet’s coma crosses the perpendicular thread, it is easy to find the diameter of the coma in angular minutes by the formula
d \u003d 0.25 * t * cos (b)
where (b) is the declination of the comet, t is the period of time. This method cannot be used for comets in the near-polar region with (b)\u003e + 70g!
- Comparison method. Its principle is based on measuring the comet's coma by the known angular distance between the stars located near the comet. The method is applicable in the presence of a large-scale atlas, for example, Cartes du Ciel.
Its values \u200b\u200brange from 0 to 9.
0 - a completely diffuse object of uniform brightness; 9 - almost a star-shaped object. This can be most clearly represented from the figure.
Determination of comet tail parameters
When determining the length of the tail, the fidelity of the estimate is greatly influenced by the same factors as when evaluating the comet's coma. Especially the urban flare affects, underestimating the value and several times, so the city will certainly not get the exact result.
To estimate the length of the comet’s tail, it is best to use the comparison method for the known angular distance between the stars, since with a tail length of several degrees, you can use small-scale atlases accessible to everyone. Small tails require a large-scale atlas, or a micrometer, since the drift method is suitable only when the tail axis coincides with the declination line, otherwise additional calculations will have to be performed. If the tail is longer than 10 degrees, it must be estimated using the formula, since due to cartographic distortions the error can reach 1-2 degrees.
D \u003d arccos *,
where (a) and (b) are the right ascension and declination of the comet; (a ") and (b") - right ascension and declination of the end of the tail of the comet (a - expressed in degrees).
Comets have several types of tails. There are 4 main types:
Type I - direct gas tail, almost coinciding with the radius vector of the comet;
Type II - a gas-dust tail slightly deviating from the radius vector of the comet;
Type III - a dust tail creeping along the comet’s orbit;
IV type - abnormal tail directed towards the sun. It consists of large dust particles that the solar wind is not able to push out from a comet's coma. A very rare phenomenon, I happened to observe it only in one comet C / 1999H1 (Lee) in August 1999.
It should be noted the fact that a comet can have both one tail (most often of type I) and several.
However, for tails whose length is more than 10 degrees, due to cartographic distortions, the position angle should be calculated by the formula:
Where (a) and (b) are the coordinates of the comet's nucleus; (a ") and (b") are the coordinates of the end of the comet's tail. If a positive value is obtained, then it corresponds to the sought, if negative, then 360 must be added to it to get the desired.
In addition to the fact that you eventually received the photometric parameters of the comet in order to be able to publish them, you must specify the date and time of observation according to universal time; tool characteristics and its increase; evaluation method and source of comparison stars, which was used to determine the brightness of the comet. Then you can contact me to send this data.
Subject: Astronomy.
Class: 10 11
Teacher: Elakova Galina Vladimirovna.
Place of work: Municipal budgetary educational institution
"Secondary school No. 7", Kanash of the Chuvash Republic
Verification work on the subject "Comets, meteors and meteorites."
Testing and evaluating knowledge is a prerequisite for the effectiveness of the educational process.
Test thematic control can be carried out in writing or in groups with different
level of training. Such a check is fairly objective, time-saving,
provides an individual approach. Students can also use tests.
to prepare for offsets and CDF. Use of the proposed work does not exclude
the use of other forms and methods of testing the knowledge and skills of students, such as
oral interview, preparation of design work, abstracts, reports, essays, etc.
Option I:
1. What was the general historical view of comets?
2. Why is the comet moving away from the Sun with its tail forward?
A. Comet tails are formed as a result of the pressure of solar radiation, which
always directed away from the sun, so the tail of a comet is always directed away from the sun.
B. Comet tails are formed as a result of the pressure of solar radiation and solar
winds that are always directed away from the Sun, so the comet’s tail is also always directed
from the sun.
B. Comet tails are formed as a result of the solar wind, which is always directed
from the sun, so the tail of the comet is always directed away from the sun.
3. What is a shooting star?
A. Very small solid particles orbiting the sun.
B. This is a streak of light that becomes visible at the time of the complete combustion of the meteor
body.
C. This is a piece of stone or metal that has flown from the depths of space.
4. How can an asteroid be distinguished from a star in a starry sky?
A. By movement relative to the stars.
B. In elongated (with large eccentricity) elliptical orbits.
B. Asteroids do not change their position in the starry sky.
5. Is it possible to observe meteors on the moon?
A. Yes, meteors can be observed everywhere.
B. No, due to lack of atmosphere.
Q. Yes, meteors can be observed on the moon, since the lack of atmosphere does not play a role.
6. Where in the solar system are the orbits of most asteroids? Than
do the orbits of some asteroids differ from the orbits of large planets?
A. Between the orbits of Uranus and Jupiter. Orbits are characterized by low eccentricity.
B. Between the orbits of Mars and Jupiter. Orbits are characterized by low eccentricity.
B. Between the orbits of Mars and Jupiter. Orbits are characterized by a large eccentricity.
7. How was it determined that some asteroids are irregular in shape?
A. By changing their apparent brightness.
B. By movement relative to the stars.
B. In elongated (with large eccentricity) elliptical orbits.
8. What is the peculiarity of the asteroids that make up the group of “Trojans”? Answer
justify.
A. Asteroids together with Jupiter and the Sun form an equilateral triangle and
move around the Sun in the same way as Jupiter, but only ahead of it.
B. Asteroids together with Jupiter and the Sun form an equilateral triangle and
move around the Sun in the same way as Jupiter, but either in front of it or behind it.
B. Asteroids together with Jupiter and the Sun form an equilateral triangle and
move around the Sun in the same way as Jupiter, but only behind it.
9. Sometimes two tails form in a comet, one of which is directed towards
To the sun, and the other from the sun. How can this be explained?
A. The tail directed towards the Sun consists of larger particles for which the force
solar attraction is more than the repulsive power of its rays.
10. Flying past the Earth at a distance of 1 AU the comet has a tail with
angular
0 °. 5. Estimate the length of the comet's tail in kilometers.
≈
1.3 ∙ 106 km.
A.
≈
B.
13 ∙ 106 km.
≈
IN.
0.13 ∙ 106 km.
Option II:
1. What are the modern astronomical ideas about comets?
A. Comets were considered supernatural phenomena that bring people misfortune.
B. Comets are members of the solar system that obey their movement
the laws of physics and have no mystical meaning.
2. Indicate the correct answers to changes in the appearance of the comet as it
orbiting around the sun.
A. The comet is far from the Sun, it consists of a core (frozen gases and dust).
B. As you approach the Sun, a coma forms.
B. In the immediate vicinity of the sun, a tail forms.
D. As you move away from the Sun, the cometary substance freezes.
D. At a great distance from the Sun, the coma and tail disappear.
E. All answers are correct.
3. Select the correct name for each description: (a) “Shooting Star”. 1.
Meteor; (b) A small particle orbiting the sun. 2. Meteorite; (in)
A solid body reaching the surface of the earth. 3. Meteoric body.
A. (a) 1; (b) 3; (in 2.
B. (a) 3; (b) 1; (in 2.
B. (a) 2; (b) 1; (at 3.
4. Achilles, Quaar, Proserpine, Themis, Juno. Specify unnecessary in this list
and justify your choice.
A. Achilles is a name taken from ancient mythology, the asteroid of the main belt.
B. Kvaar - he belongs to the Kuiper belt, named after the deity of the creator in
tongwa Indians.
V. Proserpine is a name taken from ancient mythology, an asteroid of the main belt.
G. Themis is a name taken from ancient mythology, an asteroid of the main belt.
D. Juno is a name taken from ancient mythology, the asteroid of the main belt.
5. What changes in the movement of comets cause disturbances from
Jupiter?
A. The shape of the comet’s orbit is changing.
B. The period of revolution of the comet changes.
B. The shape of the orbit and the period of revolution of the comet are changing.
6. What is the state of the substance that makes up the nucleus of the comet and its
tail?
A. The nucleus of a comet is a solid body consisting of a mixture of frozen gases and solid particles
refractory substances, tail - rarefied gas and dust.
B. The tail of a comet is a solid body consisting of a mixture of frozen gases and solid particles
refractory substances, the core is rarefied gas and dust.
B. The nucleus and tail of the comet is a solid, consisting of a mixture of frozen gases and solid
particles of refractory substances.
7. Which of the following phenomena can be observed on the moon: meteors, comets,
eclipses, auroras.
A. Due to the lack of atmosphere on the moon, meteors and polar
radiance. Comets and solar eclipses can be seen.
B. On the moon there can be seen meteors and auroras. Comets and solar
there is no eclipse.
B. You can observe all of these phenomena.
8. How can one estimate the linear dimensions of an asteroid if its angular dimensions
can't be measured even when viewed through a telescope?
A. Knowing the distance from the Earth and from the Sun, and taking some average value
reflectivity of the surface of an asteroid, its linear dimensions can be estimated.
B. Knowing the distance from the Earth and from the Sun, we can estimate its linear dimensions.
B. Knowing some average reflectivity of the surface of the asteroid
you can evaluate its linear dimensions.
9. “If you want to see a comet worthy of attention, you need to get outside
our solar system, where they can turn around, you know? I am a friend
mine, I saw there such instances that could not even fit into orbits
of our most famous comets, their tails would certainly hang out. ”
Is the statement true?
A. Yes, since outside the solar system and far from other similar systems
comets have such tails.
B. No, because outside the solar system and far from other similar systems
comets have no tails and are of negligible size.
10. Compare the causes of the glow of the comet and the planet. Can you notice
differences in the spectra of these bodies? Give a detailed answer.
Answers:
Option I: 1 - A; 2 - B; 3 - B; 4 - A; 5 B; 6 - B; 7 - A; 8 - B; 9 - A; 10 - A.
Option II: 1 - B; 2 - E; 3 –A; 4 B; 5 - B; 6 - A; 7 - A; 8A; 9 - B;
.α
Option I:
Problem Solving No. 10: Assume that the comet's tail is perpendicular to the beam
view. Then its length can be estimated as follows. Denote the angular size of the tail
/ 2α can be found from a right triangle, one of the legs
Half this corner
which is half the length of the tail of the comet p / 2, and the other is the distance from Earth to
° .5 is small; therefore, we can approximately assume that
comets L. Then tg
its tangent is equal to the angle itself (expressed in radians). Then we can write that α
≈
150 ∙ 106 km, we get p
Hence, recalling that the astronomical unit is
1.3 ∙ 106 km.
α
/ 2 \u003d p / 2 L. Angle 0
150 ∙ 106 ∙ (0.5/57)
p / L.
≈ α ≈
L ∙
There is another assessment option. You may notice that the comet flies from Earth to
a distance equal to the distance from the Earth to the Sun, and its tail has an angular size,
equal to the apparent angular diameter of the sun in the earth's sky. Therefore linear
the size of the tail is equal to the diameter of the Sun, the value of which is close to that obtained above
the result. However, we have no information on how the comet’s tail is oriented in
space. Therefore, it should be concluded that the estimate of the tail length obtained above is
this is the minimum possible value. So the final answer looks like this: length
the comet's tail is at least 1.3 million kilometers.
Option II:
Solution to Problem 4: Extra Kvaar, because he belongs to the Kuiper belt. All
the remaining objects are the asteroids of the main belt. All listed asteroids of the main
the belts have names taken from ancient mythology, and the name “Kvaar” clearly has
other semantic roots. Kvaoar was named after the Indians creator deity
tongwa tribe.
The solution to problem No. 10: The nucleus of the comet and the dust located in the head and tail of the comet,
reflect sunlight. The gases that make up the head and tail themselves glow due to
energy received from the sun. Planets reflect sunlight. So in both
in the spectra, absorption lines characteristic of the solar spectrum will be observed. TO
to these lines in the spectrum of the planet is added the absorption lines of gases constituting
the atmosphere of the planet, and in the comet's spectrum - the emission lines of the gases included
comets.
Literature:
1. G.I. Malakhova, E.K. Stratus “Didactic Material on Astronomy”: A Handbook for
teachers. M .: education, 1989.
2. Moshe D. Astronomy: Prince. for students. Per. from English / Ed. A.A. Gurstein. - M .:
Enlightenment, 1985.
3. V.G. Sourdin. Astronomical Olympiads. Problems with solutions - Moscow, Publisher
Educational-scientific center of pre-university training of Moscow State University, 1995.
4. V.G. Sourdin. Astronomical problems with solutions - Moscow, URSS, 2002.
5. Tasks of the Moscow Astronomical Olympiad. 19972002. Ed. O.S.
Ugolnikova, V.V. Chichmarya - Moscow, MIOO, 2002.
6. Tasks of the Moscow Astronomical Olympiad. 20032005. Ed. O.S.
Ugolnikova, V.V. Chichmar - Moscow, MIOO, 2005.
7. A.M. Romanov. Interesting questions in astronomy and not only - Moscow, ICMMO,
2005.
8. All-Russian Olympiad for astronomy students. Autost. A.V. Zasov et al. -
Moscow, Federal Agency for Education, AIC and PPRO, 2005.
9. The All-Russian Olympiad of students in astronomy: the content of the Olympiad and
preparation of contestants. Autost. O. S. Ugolnikov - Moscow, Federal Agency
by education, AIC and PPRO, 2006 (in press).
Internet resources:
1. The official website of all All-Russian Olympiads, created on the initiative
Ministry of Education and Science of the Russian Federation and the Federal Agency for
education http://www.rusolymp.ru
2. The official website of the All-Russian Astronomical Olympiad
http://lnfm1.sai.msu.ru/~olympiad
3. The site of the Astronomical Olympiads of St. Petersburg and the Leningrad Region -
tasks and solutions http://school.astro.spbu.ru
