How to find the Andromeda Nebula in the starry sky? Constellation Andromeda: description and interesting facts.

Astronomical observations are a very exciting activity that can “hook” any person. The night sky reveals a wide variety of objects that can be observed through a telescope, binoculars, or even with the naked eye. However, it often happens that it is difficult for a novice amateur to begin making observations. It’s good if there is a Moon and bright planets that stand out against the background of stars in the sky. What if not? Unfamiliar star patterns are usually simply confusing, and a beginner quickly loses interest in the sky.

Of course, if you want to gain experience in astronomical observations, you need to start by studying the constellations. Knowledge of the basic star patterns will allow you to navigate well in the sky and in the future find a wide variety of celestial objects - from comets to distant galaxies. But you often hear that learning constellations is boring. In this case, you can combine the useful with the pleasant and, together with the constellations, find other celestial objects: planets, nebulae, star clusters.

A modern city dweller has no idea how many interesting things can be seen in the sky with the naked eye, without the help of any optics! We are not used to looking at the night sky due to strong light pollution. However, even in urban conditions (unless you are a resident of a metropolis) it is possible to see fairly faint celestial objects. To do this, first of all, you should find a place protected from street lights. A park, city outskirts, or even a corner of a house will do. By finding cover and giving your eyes time to adjust to the darkness, you'll be surprised at how many faint stars appear in your field of vision.

In the mid-autumn evenings, the constellations dominate in the south Pegasus And Andromeda. Start your acquaintance with the sky with these constellations! They are easy to find, and most importantly, they will become a reference point for finding other autumn constellations and the famous M31 galaxy, known as Andromeda Nebula.

To find the constellation Pegasus, look south after 20:00. Halfway from the horizon to the zenith, a large square of four stars of almost equal brightness will catch your eye. This drawing (without the upper left corner) is the most noticeable part of the Pegasus constellation. On the left, a chain of stars curved upward adjoins the square, forming together with the square a figure vaguely reminiscent of a ladle with a handle. The stars of the pen, including the upper left star of the square, belong to the constellation Andromeda.

The constellations Pegasus and Andromeda are visible high in the southern sky on October evenings. Drawing: Stellarium

Andromeda and Pegasus are the main and most expressive constellations of mid-autumn. Of course, in the early evening, they are still visible in their place, and closer to night, much brighter winter constellations rise in the east. But in the evenings in October, Pegasus and Andromeda reign in the sky.

In the constellation Andromeda there is Andromeda Nebula, a giant spiral galaxy located 2 million light years from Earth. Many will be surprised, but the Andromeda Nebula can be seen with the naked eye. This is not easy to do in a city, but under good atmospheric conditions the author of these lines was able to observe the galaxy even in a city with a population of half a million people.

How to find the Andromeda Nebula? Start from the top left edge of the Pegasus Square. Follow the handle of the “bucket” to the star Mirakh (β Andromeda). Above it you will see two dim stars, denoted by the Greek letters mu (μ) and nu (ν). The Andromeda nebula is located just above and to the right of ν Andromeda.

The Andromeda nebula is located above the star Mirach, the middle one in Andromeda's arm. In the figure, the nebula is shown as an elongated nebula. Drawing: Stellarium

Look closely at this part of the sky. If you don't notice a faint hazy glow, try looking at the area with your peripheral vision. Shake your head slightly from side to side. If you see the star Andromeda Nu clearly enough, most likely your peripheral vision will “catch” the movement of the faint speck.

Pegasus Square, Andromeda constellation and Andromeda Nebula. The galaxy is located above the star Mira and the stars μ and ν Andromeda. Drawing: Stellarium

Remember that the light coming from the galaxy traveled two million light years. How far is this distance? Do the math for yourself: the speed of light is 300 thousand km/s, and the time it took to fly to Earth is 2 million years... Just think, at the time when this light started to reach Earth, there was no man on our planet yet!

The Andromeda nebula is the most distant object in space visible to the naked eye. Try and see it in mid-October, while the moonlight does not interfere with observations!

The Andromeda nebula is the closest large galaxy to us. Even in amateur photographs she looks amazing. Photo: Julian Wessel

Big galaxy. Contains approximately 1 trillion stars, which is 2.5-5 times larger than the Milky Way. It is located in the constellation Andromeda and is 2.52 million light years away. years. The plane of the galaxy is inclined to the line of sight at an angle of 15°, its apparent size is 3.2 × 1.0°, its apparent magnitude is +3.4 m.

Observation history

The first photograph of the Andromeda Galaxy taken by Isaac Roberts

The first written mention of the Andromeda Galaxy is contained in the Catalog of Fixed Stars by the Persian astronomer Al-Sufi (946), who described it as a “small cloud”. The first description of the object, based on observations using a telescope, was made by the German astronomer Simon Marius in 1612. When creating his famous catalog, Charles Messier listed the object under the designation M 31, erroneously attributing the discovery to Marius. In 1785, William Herschel noted a faint red speck in the center of M 31. He believed that the galaxy was the closest of all nebulae, and calculated its distance (totally unrealistic) to be equivalent to 2000 times the distance between Sirius and Sirius.

In 1864, William Huggins, observing the spectrum of M 31, discovered that it differed from the spectra of gas and dust nebulae. The data indicated that M 31 consisted of many individual stars. Based on this, Huggins assumed the stellar nature of the object, which was confirmed in subsequent years.

In 1885, SN 1885A, known in the astronomical literature as S Andromeda. In the entire history of observations, this is so far only one such event recorded in M ​​31.

The first photographs of the galaxy were taken by Welsh astronomer Isaac Roberts in 1887. Using his own small observatory in Sussex, he photographed M 31 and determined the object's spiral structure for the first time. However, at that time it was still believed that M31 belonged to our Galaxy, and Roberts mistakenly believed that it was another solar system with forming planets.

The radial velocity of the galaxy was determined by the American astronomer Vesto Slipher in 1912. Using spectral analysis, he calculated that M 31 was moving towards the Sun at a speed unheard of for known astronomical objects of that time: about 300 km/s.

Experts from the Harvard-Smithsonian Center for Astrophysics, analyzing the results of 10 years of observations of M 31 using Chandra, discovered that the glow of matter falling on the core of the Andromeda galaxy was dim until January 6, 2006, when a flare occurred that increased the brightness of M31 * in the X-ray range by 100 times. Further, the brightness decreased, but still remained 10 times more powerful than before 2006.

General characteristics

Movement in the Local Group

The Andromeda Galaxy in ultraviolet rays.

Andromeda Galaxy, like Milky Way, belongs to the Local Group, and moves towards the Sun at a speed of 300 km/s, thus it belongs to objects with a violet shift. Having determined the direction of the Sun's movement across the Milky Way, astronomers found that the Andromeda Galaxy and our Galaxy are approaching each other at a speed of 100-140 km/s. Accordingly, the collision of two galactic systems will occur in approximately 3-4 billion years. If this happens, they will both most likely merge into one large galaxy. It is possible that in this case ours will be thrown into intergalactic space by powerful gravitational disturbances. The destruction of the Sun and, most likely, will not occur during this process.

Structure

The Andromeda Galaxy is the largest in the Local Group: based on data obtained using space telescope, astronomers have found that it contains about a trillion. She has several: M 32, M 110, NGC 185, NGC 147 and possibly others. Its extent is 260,000 light years, which is 2.6 times greater than the Milky Way.

Core

In the core of M 31, as in many other galaxies (including the Milky Way), there is a candidate for (SMBH). Calculations have shown that its mass exceeds 140 million solar masses. In 2005, a space telescope discovered a mysterious disk of young blue stars surrounding a black hole. They orbit around a relativistic object, just like the planets around the Sun. Astronomers were puzzled by how such a donut-shaped disk could form so close to such a massive object. According to calculations, the monstrous tidal forces of the SBS should not allow it to condense and form new stars. Further observations may provide a clue.

Double galactic core

The discovery of this disk added another argument to the theory of existence. Astronomers first discovered blue light in the core of M 31 back in 1995 using the Hubble telescope. Three years later, the light was identified as a cluster of blue stars. It was only in 2005, using a spectrograph mounted on the telescope, that observers determined that the cluster consists of more than four hundred stars that formed approximately 200 million years ago. The stars are grouped into a disk with a diameter of only 1 light year. Older and cooler red stars, previously discovered by Hubble, nest in the center of the disk. The radial velocities of the disk stars were calculated. Thanks to the gravitational influence of the black hole, they turned out to be record high - 1000 km/s (3.6 million kilometers per hour). At this speed, you can fly around the globe in 40 seconds or get from Earth to six minutes.

In addition to the black hole and the disk of blue stars, there are other objects in the galactic core. In 1993, a binary was discovered at the center of M 31, which came as a surprise to astronomers, since the two clusters merge into one in a fairly short period of time: about 100 thousand years. According to calculations, the merger should have occurred many millions of years ago, but for strange reasons this did not happen. Scott Tremaine ( Scott Tremaine) from Princeton University proposed to explain this by the fact that in the center of the galaxy there is not a double cluster, but a ring of old red stars. This ring may look like two clusters because we only see stars on opposite sides of the ring. Thus, this ring should be located at a distance of 5 light years from the black hole and surround a disk of young blue stars. The ring and the disk are turned to us with one side, which may indicate their interdependence.

Studying the center of M 31 using the XMM-Newton space telescope, a team of European researchers discovered 63 discrete sources x-ray radiation. Most of them (46 objects) are identified with low-mass binary X-ray stars, while the rest are either black hole candidates in binary systems.

Other objects

Globular cluster Mayall II

About 460 globular clusters have been recorded in the galaxy. The most massive of them, Mayall II, also called G1, has the highest luminosity in the Local Group, surpassing in brightness the brightest cluster in the Milky Way, Omega Centauri. It is located at a distance of about 130 thousand light years from the center of the Andromeda galaxy and contains at least 300 thousand old stars. Its structure, as well as the stars belonging to different populations, indicate that it is most likely the core of an ancient dwarf galaxy that was once absorbed by M31. According to research, at the center of this cluster there is a black hole candidate with a mass of 20 thousand Suns. Similar objects also exist in other clusters.

In 2005, astronomers discovered M 31 in the halo new look star clusters. Three newly discovered clusters contain hundreds of thousands bright stars- with almost the same amount as in globular clusters. But what sets them apart from globular clusters is that they are much larger—several hundred light-years in diameter—and also that they are less massive. The distances between the stars in them are also much greater. Perhaps they represent a transitional class of systems between globular clusters and dwarf spheroidal galaxies.

The galaxy contains orbiting star PA-99-N2, the first to be discovered outside the Milky Way.

Satellite galaxies

The Andromeda Galaxy, like our Milky Way, is surrounded by several dwarf galaxies - small star systems consisting of several billion stars. The largest and most famous of them are the compact M 32 and M 110, visible in any photograph of the Andromeda Galaxy. Calculations show that M 32 may have been spiral in the recent past, but the process that supported the formation of its spiral arms was suppressed by the powerful tidal forces of the Andromeda Galaxy. M 110 is also involved in gravitational interaction with the Andromeda Galaxy: astronomers discovered a gigantic stream of stars rich in heavy metals on the periphery of M 31 - in its halo. Similar stars also inhabit dwarf M 110, which indicates their migration from one galaxy to another.

During long-term observations with the help of Canada-France-Hawaii, a whole group of dwarf galaxies orbiting in the same plane around M 31 was discovered (the work was published in early 2013).

Observations of the Andromeda Nebula

The Andromeda nebula is one of the few extragalactic objects that can be seen with the naked eye. For an observer from Earth, the area occupied on the celestial sphere is seven times larger than the disk of the Moon, but only the core of the galaxy is clearly visible. Binoculars are required to view the details of the structure.

To locate a galaxy, you first need to find the North Star (α Ursa Minor, the last star of the "Little Dipper" handle). Then you need to find Cassiopeia. In Cassiopeia we are looking for the brightest star - α Cassiopeia (second lower corner, if the observer sees Cassiopeia in the form of the letter W). After this, you need to draw a line connecting these two stars and, continuing to move in the direction from the North Star, find the Great Square. The first star in this direction will be Alferaz, which belongs to both the Great Square and Andromeda. This star is the “head” of Andromeda, from which two curved lines extend - “legs”. On the one that is closer to Cassiopeia, you need to count the third star (from head to toe). Above it (if Cassiopeia is also on top) the Galaxy will be located, which is visible to the naked eye as a dim, blurry star, and when viewed through binoculars it resembles a small elliptical cloud.

Neighbors in the sky from the Messier catalog

• M 32 and M 110 - satellites of the Andromeda Nebula;
• M 33 (in the Triangulum, to the south - on the other side of β And) is a large spiral galaxy, its plane facing us;
• M 76 (to the northeast, in the constellation Perseus) - a small planetary nebula “Little Dumbbell”;
• M 34 (to the east, also in the constellation Perseus) is a fairly bright open cluster.



M31 "Andromeda Nebula".
11/28/2010, Deepsky 80\560ED telescope, WO 0.8x II gear-corrector, Canon 1000D, ISO 1600, shutter speed 1 minute, 10-15 frames. Mount - EQ5

How to find the famous Andromeda Nebula (M31)? Best time The best time to observe it is in autumn, but you can also try to find it at other times of the year (for example, in the morning in summer). To search, you must first face the northern part of the sky, find the constellation Ursa Major, draw a line from the handle of the “bucket” through the North Star, and on the continuation of this imaginary line you will see an inverted letter M or W - this is the constellation Cassiopeia. Cassiopeia is a fairly bright constellation, so you can easily find it.


Then we turn to the right, to the southeastern side of the sky - we see that under Cassiopeia there are two large constellations - Andromeda and Pegasus. Feature- the so-called “Pegasus Square” - four stars forming a kind of “square”.


We will orient ourselves from it - draw an imaginary line along the stars, first to the left and then up. If you did everything correctly and look at the desired place through binoculars, telescope or a good optical finder - you will see a small light oval cloud. Congratulations, this is the Andromeda Nebula - a huge galaxy with which our Galaxy is approaching (the collision will occur in 3-4 billion years).




In small telescopes it is visible in the same way as in binoculars/spotting scopes, but larger - a large oval spot. Several of its satellites, small galaxies (M32 and M110), also become noticeable. With 20x60 binoculars, it is visible throughout the entire field of view. The visual size of the Andromeda Nebula is about 3...3.5 degrees - 7 times the apparent size of the Moon! In telescopes of larger diameters (from 250 mm and more), dust paths near the center of the galaxy become accessible for observation.
The main key to success in observations is a dark sky and the absence of flare.

In the photographs, the Andromeda Nebula looks much more beautiful than visually, primarily due to the visibility of dust clouds along the center of the galaxy. Basic images of the galaxy can be obtained with even the simplest motorized equatorial mount and a DSLR camera with a kit lens.

Which can be seen in the sky with the naked eye and is the only spiral galaxy (except for our own) that is quite reliably visible in the suburban sky. The best time to observe the Andromeda Nebula is dark, moonless autumn evenings. At this time, the galaxy is high in the sky, where the transparency of the sky is higher than at the horizon, and city light exposure is not too bothersome.

Among all the deep space objects, the Andromeda Nebula is perhaps the brightest and largest object in the autumn sky. How to find this galaxy in the sky in autumn?

There are two classic methods.

Method number 1: starting from the Pegasus Square

If the main star pattern in the summer sky is , then in the fall it is replaced by another asterism - Great Square of Pegasus. (They are often called without the “big” prefix.) The Pegasus Square after sunset is in the southeast, to the left of the Summer Triangle, and towards midnight it is in the southern sky. Find this quadrilateral. (Hint: the stars that make it up are about the same brightness as the stars of the Big Dipper, which is visible in the north at this time.)

Summer Triangle and Pegasus Square in the autumn sky. Drawing: Stellarium

Adjacent to the square on the left a chain of three stars of approximately comparable brilliance. The chain bends upward, making the Pegasus square look like a huge coffee pot. The stars in this chain belong to the Andromeda constellation.

Now pay attention to the middle star in the chain, or rather, to its surroundings: above it you will see two more stars - much dimmer. This is by the way good test - If you can confidently see these stars, then most likely you will be able to see the Andromeda Nebula . If you see two stars with difficulty, then the quality of the sky is not good, and you will have to use binoculars or a telescope to find the Andromeda Galaxy. (There's nothing wrong with that, it's just that not everyone has them!)

So, there is one last step left. The Andromeda nebula is located just above and to the right of the second star, called Andromeda nude.

Pegasus Square, Andromeda constellation and the Andromeda Nebula (circled). Drawing: Stellarium

Method number 2: starting from the constellation Cassiopeia

The constellation Cassiopeia is familiar to many thanks to its characteristic pattern - it looks like the letter M or Latin letter W. This small constellation visible in our sky all year round. In autumn, in the evenings, Cassiopeia can be observed in the eastern part of the sky at an altitude of about 60° above the horizon, and at midnight - at the zenith.

The constellation Andromeda is located under the constellation Cassiopeia. If in the figure W we take the third and fourth stars (counting from left to right), mentally connect them with a line and extend this line three times the distance down (slightly at an angle, as in the figure), then this line will point to the Andromeda Nebula.

The Andromeda Nebula can be found by starting from the stars of Cassiopeia. Drawing: Stellarium

Both search options are equally simple. Perhaps the first method is somewhat more reliable, since it gives the position of the nebula directly next to the star. But you can easily combine two methods - say, find the constellation Andromeda from the constellation Cassiopeia, and the Andromeda Nebula using two stars.

Now a few words about What does a galaxy look like to the naked eye?. On dark sky it will appear as a dim elongated speck the size of half the visible disk of the Moon. You won't be able to discern any details. If the sky transparency is mediocre, the galaxy may not be visible to direct vision or may be very poorly visible. Then use peripheral vision, that is, look slightly away from the place where the Andromeda Nebula is located, and at the same time try to catch its faint glow.

It goes without saying that it is extremely difficult to see the Andromeda Galaxy in the city. Success depends heavily on the quality of the atmosphere and the choice of location. Try to find an area that is protected from street lighting as much as possible. Never watch under the moon! Before observing, give your eyes 10 minutes to adjust to the darkness. During this time, remain in complete darkness. The rest depends on your patience, experience and atmospheric conditions.

Cold autumn evening... Distant stars tremble and twinkle above the tops of yellowed trees. In the south you can see the Great Summer Triangle - the three brightest stars. But its time passes: closer to midnight, the triangle approaches the horizon, and on the southern slope the place is occupied by a large bucket of the constellations Pegasus and Andromeda.

For more than two thousand years, since the times of Hipparchus and Eratosthenes, the constellation of the autumn sky Andromeda has been flickering brightly among a scattering of distant stars.

Legend of the constellation Andromeda

In a time when magic ruled the world, in the era of the gods of Olympus, King Cepheus ruled in a distant country called Ethiopia. He had a wife, Cassiopeia, and a daughter, Andromeda.

And everything would be fine in the country of King Cepheus if it were not for the boasting of his lovely wife Cassiopeia. Once the king’s wife boasted that she was more beautiful than the Nereids and nymphs. The sea beauties heard about this. The resentment overflowed, and they complained to the god of the seas, Poseidon. Being his daughters and granddaughters, they understood that he would listen to them and would not leave the terrible insult unpunished.

Then Poseidon became angry and sent a terrible monster to Ethiopia. The Terrible Whale constantly came out of the sea and destroyed the country. Then King Cepheus was saddened, having learned the whole truth from his wife, and went for advice to the oracle of Zeus. He listened to him and advised him to give his daughter Andromeda to the monster - Keith, in order for peace to come in the country. But how could you sacrifice your own daughter? In complete confusion, Cepheus wandered home. After some time, the people learned about the oracle's advice and forced the king to resolve this issue.

Pay

Andromeda, chained to a rock, awaited her death with horror.

But suddenly Perseus suddenly appeared, having learned the whole truth, he began to wait for the monster to fight him.

Happy ending to the story

As in any good mythical legend, good triumphed over evil.

But there were some incidents. Andromeda was betrothed to Finney, brother of Cepheus. He appeared at the wedding of Perseus and Andromeda and demanded the return of the bride. But Perseus was not going to give up the beautiful bride. He took out the head of the Gorgon Medusa and turned Phineus into stone. This is the story of the times of magic and the gods. And we will involuntarily remember her, watching in the sky how brightly Andromeda flickers - the constellation, the legend of which is so beautiful and instructive.

How to find Andromeda in the sky?

After reading interesting legend, most likely, you will want to see Andromeda with your own eyes. It's not difficult to find. The easiest time to spot the constellation is in the fall. Between September and early December, the constellation Andromeda can be seen from early twilight until morning. In the evening, the asterism is in the east, a little closer to midnight - in the south. Closer to morning it shifts to westward. First you will need to find a giant quadrangle - the Pegasus Square.

To the left of the Square you can see a chain of stars of the same luminosity. These are precisely the stars of the Andromeda constellation.

You can find the desired asterism in another way. First, find the constellation Cassiopeia, it looks like the letter M or W, depending on the position of the asterism in the sky. The Andromeda stars are located directly below this “letter”. With the onset of December, the constellation Andromeda shifts to the west. Closer to spring, the asterism is already in the northwest direction. And with the approach of summer, it comes out only at dawn, and it is quite difficult to notice it.

The city lights are fading and the stars are shining

Of course, even for a person with a rich imagination it is difficult to imagine a girl looking at the “handle” in the sky. However, these three stars are not the entire constellation - Andromeda (photo below) occupies much large area in the sky. On the northern side, the asterism is bordered by the constellations Pegasus and Cassiopeia, on the south by the Triangle and Pisces, and on the west by the Lizard and Pegasus.

However, to see all the stars of the Andromeda constellation, you will need to travel outside the city limits, where there is no night light. Once you get used to the darkness a little, you will be amazed a huge number stars in the sky that are visible to the naked eye. Take a look at our constellation Andromeda - Alpha Andromeda forms the upper left corner of Pegasus Square - the girl's head. The following objects δ, σ and θ form Andromeda's shoulders, β, μ and ν constellations form her waist. Other objects are γ and M51 Andromeda - her legs. The girl's hands are marked with stars λ on one side and ζ on the other.

You see that the girl’s arms are spread out to the sides. Why? The answer is obvious: she is chained to a rock. If you look closely, the Andromeda constellation really resembles the figure of a girl chained to a rock.

Taking a walk away from the city lights, you saw how the “handle” took on the shape of a girl from an ancient legend.

Some terms in simple language

It may be a little difficult to remember or understand some of the description.

We will explain to you in simple language Some terms and expressions used in the article:

1. Giants are stars much larger than our Sun (which is a yellow dwarf).
2. Temperature in Kelvin is 273 degrees higher than Celsius (0 degrees Celsius translates to 273 degrees Kelvin).
3. A light year is the distance that light travels in one year (for example, light travels from the Sun to Earth in 8 minutes 19 seconds).
4. Often referred to as "spectral class" - scientists determine the temperature of a distant star using a certain spectrum (like a rainbow with different widths of bands of all colors).
5. The stars of constellations (objects) are designated, starting with the brightest, using the Greek alphabet: α, β, γ and so on. They may also have a separate name. For example: Alferats or α Andromeda.

Constellation Andromeda: description of stars

Let's start with the brightest star of our asterism.

Alferaz is the brightest star in the constellation Andromeda, with Arabic translated means “navel of a horse.” From antiquity and the Middle Ages to the 17th century, this star belonged simultaneously to two constellations - Pegasus and Andromeda.

Alferaz is a blue subgiant with a temperature of 13,000 degrees Kelvin, emitting light 200 times more than the Sun. It is located 97 light years from Earth. A study of the spectrum showed that Alferaz is a pair star. It is considered a prominent representative of an amazing class of mercury-manganese stars.

Their atmosphere may contain an excess of europium, gallium, mercury and manganese, and the proportion of all other elements is insignificant. Scientists suggest that main reason The anomalies may be strongly influenced by the radiation and gravity of the star.

β constellation Andromeda - Mirax, a fairly large object, belongs to the group of red giants.

Alamak - γ Andromedae, is the third brightest star in the constellation. This complex system, which consists of four bright components. Alamak is one of the beautiful double stars that can be observed even through a small telescope. Its main yellow star has a bluish companion and is considered a giant of spectral class K3. The object's temperature reaches about 4500 K. Almak's radius is 70 times greater than that of our star.

These are the main characteristics of the three brightest stars in the Andromeda constellation.

So where was the rock that Andromeda was chained to? This question was asked by many geographers of the past. According to Strabo, the rock was located in Iop, near the city of Tel Aviv. The Jewish chronicler Josephus (1st century AD) even claimed that imprints of Andromeda's chains and the remains of a monster could be found on the shore!

As for Ethiopia, it is quite far from Israel. Obviously, this rock was located on the shores of the Red Sea, and Andromeda herself was a black woman. True, according to Herodotus, all the events described took place on the territory of India. Definitely the question remains open. It is quite possible that the legend told about real events, but transformed into a kind of myth that has survived to our time.