Cassiopeia (lat. Cassiopeia) - constellation northern hemisphere sky.

• The brightest stars of Cassiopeia (from 2.2 to 3.4 magnitudes) form a figure similar to the letters "M" or "W".
• The constellation occupies an area of ​​598.4 square degrees in the sky and contains about 150 stars visible to the naked eye; of which 90 stars are brighter than 6m.
• Most of the constellation lies in the band Milky Way and contains many open star clusters.

The constellation Cassiopeia is almost entirely immersed in the so-called summer Milky Way, which already indicates that this constellation can be very rich in objects of deep space.

Indeed, in Cassiopeia there are more than two dozen wonderful open star clusters, therefore the main tool for us today will be powerful astronomical binoculars, or a fast refractor with an aperture of at least 100 mm and a wide field of view. The constellation Cassiopeia is non-setting in almost the entire territory of Russia. Only in the very south of the country a small part of it briefly hides behind the horizon.

The myth of the constellation Cassiopeia

Cassiopeia was the wife of the king of Ethiopia, Cepheus (located next to her in the form of a constellation). Once she boasted that her beauty was superior to nerids (50 sea nymphs created by the titan Nereus). They got angry and asked Poseidon to punish her. He could not refuse, as he was married to one of them (Amphitrite). He sent Cetus, a sea monster depicted in the constellation of Cetus, who was supposed to destroy the kingdom. The king asked the oracle for help, and he advised to give Poseidon his daughter Andromeda. With great difficulty they agreed and chained her to a rock. But at the last moment she was saved by Perseus, whom she later married. However, this is not the final. One of her admirers, Phineus, showed up at the wedding and accused her of treason, since only he had the right to marry her. A fight took place in which Perseus used the head of the Gorgon Medusa. But because many people looked at her, the king and queen also turned to stone. Poseidon sent Cassiopeia and Cepheus to heaven. But he nevertheless punished her, since for half a year the constellation remains wrapped upside down. Most often, she is depicted sitting on a throne and combing her hair.

How to find the constellation Cassiopeia?

The constellation Cassiopeia is usually found by the asterism Throne. It is best for someone to show this Throne - it is enough to see this configuration of stars in the sky once, and it will become recognizable forever!

Independently, the constellation Cassiopeia can be found as follows:

1. If you live approximately at the latitude of Moscow, then literally from the very beginning of autumn, going outside at about midnight local time, you will find the Tron asterism right above your head, at the zenith. You just have to correctly determine the angular dimensions of the throne and mentally build its drawing according to the stars.

The largest angular distance in the Throne asterism, between Seguin and Kaf, is about 13°. The angular distance between the thumb and forefinger of the outstretched hand of an adult is 16-18°, so the Throne against the background of the outstretched hand will look approximately as shown in Fig. 5.

Estimation of the angular size of the asterism "Throne" in the constellation Cassiopeia using an outstretched hand. This image, as it were, emphasizes the compactness of the placement of the bright stars of Cassiopeia.

1. An all-weather way to determine the location of Cassiopeia is to “aiming” the beam through already known stars. The best “shot” will turn out if you continue the line from Aliot (ε UMa) beyond the North Star (α UMa), while you get an exact hit on Gamma Cassiopeia Navi, moreover, looking closer you will find that the Big Dipper and the asterism Throne of Cassiopeia are located centrally symmetrically relative to the Pole Star.

You need to mentally draw a line through Aliot Ursa Major and the Polar Star - it will lead to the brightest star Cassiopeia Navi. There are other options: from any of the stars of the handle of the Big Dipper, also draw lines to the Polar one, all of them will lead to Cassiopeia. In such a position as in Figure 7 Ursa Major and Ursa Minor, Cassiopeia and the Throne can be seen in the late spring evening.

• If you look at the Sun from Alpha Centauri, one of the stars closest to us, then it will be in Cassiopeia and will be visible as a star of 0.5 magnitude.
• Stephen King's novel The Green Mile mentions the constellation Cassiopeia: the novel's protagonist, John Coffey, calls the constellation "Cassie the lady in the rocking chair", reflecting an American folklore reflection ancient myth. The constellation Cassiopeia is also mentioned in the novel The Langoliers.
• Also, the constellation Cassiopeia is mentioned in the movie Intuition (2001), where the main character Jonathan (John Cusack) tells the myth about the constellation to a girl named Sarah (Kate Beckinsale).
• The star alpha Cassiopeia is the goal of the expedition in the Soviet science fiction film-dilogue "Moscow - Cassiopeia / Youths in the Universe", released by the film studio. Gorky in 1973-1974.
• Cassiopeia (Cassiopeia) - the name of the official fan club of the group DBSK
• Cassiopeia in the world of Middle-earth, created by the writer J. R. R. Tolkien, corresponds to the constellation Vilvarin (Butterfly).
• Flammarion in his book "The Starry Sky and Its Wonders" tells about the work of a certain English writer "The Star ψ of Cassiopeia, amazing story one of the worlds in space, a description of the peculiar nature, habits, travels and literary works of the inhabitants there. According to the author, the manuscript of the book was found in an empty fireball found in the Himalayas.

W-asterism

Cassiopeia includes an asterism that forms a memorable image of the constellation - W-asterism. It consists of the brightest stars of the constellation, ε (Seguin), δ (Rukbach), γ (Navi), α (Shedar) and β (Kaf), forming a figure resembling the Latin letter "W".

Shedar(Alpha Cassiopeiae) is an orange giant of spectral type K0IIIa at 228 light years. This is a suspicious variable star. The apparent value may vary depending on which photometric system is used. The range contains from 2.20 to 2.23 magnitudes. It is located in the lower right corner of the W-asterism. The name Shedar is taken from the Arabic "şadr" - "chest". It marks the star position - in the heart of Cassiopeia.

cafe(Beta Cassiopeiae) is a subgiant or giant of spectral type F2 III-IV. It is 54.5 light years away from us. It is a Delta Scuti type variable star. Brighter than her in this class only Altair(star in constellation Aquila and 12th in the sky). This yellow-white star is 28 times brighter than the Sun and 4 times larger. It is currently in the process of cooling and will one day become a red giant.

Variables like Delta Scutum exhibit fluctuations in brightness due to radial and non-radial ripples on the surface. They are usually giants or main sequence stars with spectral types ranging from A0 to F5.

The mean apparent magnitude is 2.27. From the Arabic kaf is translated as "palm" (that is, the palm of the Pleiades is a well-known cluster in the constellation Taurus). Other traditional names are al-Sanam al-Naqa and al-Kaff al-Hadib.

Together with the stars Alpheratz (Andromeda) and Algenib (Pegasus), Kaph was perceived as one of the Three Guides - three bright stars that create an imaginary line from Kaph to Alpheratz to the celestial equator (the point where the Sun passes in the spring and autumn equinoxes).

Navi(Gamma Cassiopeia) is an eruptive variable star that serves as the prototype for the variable stars Gamma Cassiopeia. Shows irregular changes in brightness from 2.20 to 3.40 magnitude. It is the W-shaped central star and the brightest in the constellation (now). It is a blue star (spectral type B0.5 IVe) located 610 light-years away with a brightness 40,000 times that of the sun and about 15 solar masses. Due to the rapid rotation, it expands at the equator and creates a “maternity” disk of lost mass and material. The Chinese call it Qih - "whip". She also has the nickname "Navi" from astronaut Virgil Grissom. Navi is Ivan (in English, Ivan is the middle name of an astronaut), written in reverse order. The astronauts used the star as a guide.

Rukbach(Delta Cassiopeia) is a double star with a period of 460 days. It belongs to the spectral class A5. It is 99 light years distant and has an apparent magnitude between 2.68 and 2.74. It ranks fourth in brightness in the cluster. The name came from the Arabic - "knee". Sometimes it is called Xora.

Seguin(Epsilon Cassiopeiae) is a bright blue-white B-class giant 440 light years away. 2500 times brighter than the Sun with an apparent magnitude of 3.34. Age - 65 million years. The star is at the end of a cycle of hydrogen fusion. Differs in very weak spectral absorption of helium.

Achird(Eta Cassiopeii) is a yellow-white G-type hydrogen dwarf star, slightly cooler than the Sun. The surface temperature is 5730 Kelvin and the apparent magnitude is 3.45. It is the closest star in Cassiopeia to our system (only 19.4 light years away).

Achird has a companion, an orange K-class dwarf with an apparent magnitude of 7.51, 11 arcseconds away. Both are classified as a variable star, RS Canis Hounds. They form a close binary star and have active chromospheres that create large star spots. This leads to changes in luminosity - the brightness fluctuates by 0.05 magnitudes.

Zeta Cassiopeiae is a blue-white subgiant (B2IV) 600 light years away. The apparent visual magnitude is 3.67. It is an SPB (slowly pulsating B) variable star with a magnetic field. The rotation speed is 56 km/s, and the period is 5.37 days.

Rho Cassiopeia- a yellow hypergiant (a rare type, since there are only 7 of them in the Milky Way). It belongs to the spectral class G2Ia0e and is 11650 light years away. One of the brightest stars. Despite the distance, it can be viewed without technical equipment. It is 550,000 times brighter than the Sun with an absolute magnitude of 7.5. Apparent visual magnitude ranges from 4.1 to 6.2. This is a semi-regular variable with huge spikes every 50 years (due to this, the brightness changes). In 2000-2001, the star ejected about 10,000 Earth masses in one outburst. Scientists believe that it exploded as a supernova because it used up most of its nuclear fuel. But if this is so, then the light from the explosion has not yet reached us.

V509 Cassiopeiae is a G-type supergiant at 7800 light years. The yellow-white star belongs to semi-regular variables. Luminosity varies within 4.75-5.5.

Notable objects

• Star Tycho Brahe. In 1572, the Danish astronomer Tycho Brahe noticed the sudden appearance of a bright new star in the constellation Cassiopeia, not far from κ Cas. The new star gradually weakened and ceased to be visible after sixteen months. Today it is known that it was a supernova - one of the last explosions of stars observed in the Milky Way galaxy. About 7,500 light-years away, the supernova remnant has a diameter of nearly 20 light-years.
• Cassiopeia A. This constellation contains one of the most powerful sources of galactic radio emission - Cassiopeia A (Cas A). The flow of radio waves from this region of the sky is many times more powerful than the radio emission of the star Tycho Brahe. In 1951, photographic plates sensitive to red light recorded fragments of a small radio nebula associated with Cassiopeia-A. Based on the rate of expansion of the nebula, it was calculated that the explosion that gave rise to it occurred presumably in 1667. In the sky, this object is located between β Cassiopeia and δ Cephei.

Among other interesting objects of the constellation:

• Open star clusters M52 (NGC 7654), M103 (NGC 581), NGC 457 and NGC 7789,
• Dwarf elliptical galaxies NGC 147 and NGC 185 are satellites of the Andromeda Nebula,
• Diffuse NebulaNGC 281
• A giant sphere of gas is the Bubble Nebula (NGC 7635).
• Nebulae IC 1805, IC 1848, and IC 1795, which are associated with radio sources W4, W5, and W3, respectively.

(lat. Cassiopeia), a non-setting constellation in the northern hemisphere of the sky. brightest stars Cassiopeia(from 2.2 to 3.4 magnitude) form a figure similar to the letter "M" in December and the letter "W" in June. The constellation occupies an area of ​​598.4 square degrees in the sky and contains 150 stars visible to the naked eye; of which 90 stars are brighter than 6m. Most of the constellation lies in the band of the Milky Way and contains many open star clusters.

click on the image to enlarge it

Lat. title	Cassiopeia (genus n. Cassiopeiae)
Reduction	Cas
Symbol	Queen on the throne
right ascension	from 22 h 52 m to 3 h 25 m
declination	from +46° to +77°
Square	598 sq. degrees (25th place)
brightest stars (value< 3 m)	Shedar (α Cas)- 2.24 m Kaf (β Cas)- 2.27 m Navi (γ Cas)- var, 2.47 m Rukba (δ Cas)- 2.68 m
meteor showers
neighboring constellations	Giraffe Cepheus Lizard Andromeda Perseus
The constellation is visible at latitudes from +90° to -13°. The best time for observation is September-November.

W-asterism

The constellation Cassiopeia includes an asterism that forms its memorable shape - the W-asterism. It consists of the brightest stars of the constellation, ε (Seguin), δ (Rukbach), γ (Navi), α (Shedar) and β (Kaf), forming a figure resembling the Latin letter "W".

Stars

The brightest stars ε (Segin), δ (Rukbakh), γ (Navi), α (Shedar) and β (Kaf), forming the W figure, have magnitude 3.4, respectively; 2.7; 2.4; 2.2 and 2.3 visual magnitudes.

An unusual variable star is γ Cassiopeiae. It is a nova-like star whose brightness varies from 1.6m to 3m.

Otherwise behaves ρ Cassiopeia, which belongs to the class of supergiant stars (it is 40 times heavier and about 500,000 times brighter than the Sun). Most of the time its brightness is unchanged and close to 4m. But sometimes the brightness drops to 6.2m, and then the ρ of Cassiopeia becomes inaccessible to the naked eye. The reason for the change in brightness is the emission of gas into space by the star, which leads to a weakening of its apparent brightness.

ε Cassiopeiae is a double star. The main star (3.7m) is a yellowish giant, the companion (7.4m) is a small red cold star with a surface temperature close to 3000 K. Both stars revolve around a common center of gravity with a period of 526 years. They are relatively close to the Sun - at a distance of 20 light years.

The yellow dwarf star μ (5.3m) is notable for its very fast movement. Every second it moves away from us by almost 100 km and at the same time it is shifting in the transverse direction. In a millennium, μ Cas travels a distance in the sky equal to twice the apparent diameter of the lunar disk. For the first time, μ Cas was listed in the star catalogs by Tycho Brahe.

On the picture - painting - The king of Ethiopia Cepheus and the Cassiopeia queen thank Perseus for freeing their daughter Andromeda, La Délivrance d'Andromède (1679) Pierre Mignard, Louvre

The constellation Cassiopeia in the ancient star atlas of J. Hevelius. Open star cluster M 10 3 (NGC 581) Owl Star Cluster NGC 457 Bubble Nebula ( NGC 7635 ) A photo : Milantiev Oleg RC-360, Paramount ME, FLI PL-09000 A photo : Andrey Kuznetsov Johannes Kepler Private Observatory Nebulae IC 59 and IC 63, bright star - γ Cassiopeiae A photo : Milantiev Oleg Newton telescope (SKP25012) 254/1200mm + Canon450Da / SW Equinox 80 + QHY5 (guide) on EQ6pro

One of the most interesting constellations for an astronomer. This constellation is easy to find in the sky. it forms the letter W or M from stars. The constellation Cassiopeia is located in the region of the Milky Way and is very rich in open star clusters, which is why it is interesting for astronomical observations. But everything is in order.

Consider the stars of the constellation Cassiopeia. As mentioned above, the main stars of the constellation form an asterism in the sky in the form of the letter W or M. We list these stars ε (Segin) 3.2 m, δ (Rukbach) 2.7 m, γ (Navi) 2.4 m, α ( Shedar) 2.2m and β (Kaf) 2.3m.

Gamma Cassiopeia (Navi). The history of the name of this star is interesting. In NASA, this star was used in navigation and astronaut Virgil Ivan Grissom (Virgil Ivan Grissom) jokingly called it Navi (Navi), which is read backwards as his middle name Ivan (Ivan). Gamma Cassiopeiae is an eruptive variable star. It changes its brightness in the range from 3.4 to 2.2 sv. The change in brightness occurs due to the rapid rotation of the star, the outflow of matter and the appearance of a gaseous disk at the equator of the star. Also Gamma Cassiopeiae is the source x-ray radiation. The reason for the radiation, perhaps, lies in the accretion of matter to the companion of the star (the orbital period of the satellite is 204 days) or even with the gaseous disk of the star. Gamma Cassiopeiae is an optical binary star. In a small telescope, you can see a faint star (ADS782AB) 11 stars at a distance of 2 ".

Rho Cassiopeia is a yellow giant star. The mass of the star is 40 solar and the star shines like 500,000 suns. Rho Cassiopeii is a variable star, its brightness varies up to 6.2 stars. and it becomes inaccessible to the naked eye. The usual brightness of Rho Cassiopeia 4 stars. The reason for the decrease in the brightness of a star lies in the emissions of gas from its surface, which weaken its brilliance.

M Cassiopeii is a yellow-orange G5 type star. This is a double star. At a distance of 0.54–2.30 a.u. (the orbit is highly elongated, the eccentricity is 3.3 AU) a red dwarf revolves around it with a period of 21.75 years. The peculiarity of the star is not in this. M Cassiopeia has a fast own movement in the Galaxy, about 167 km / s ..

This Cassiopeia (Achird)- a beautiful double star of 4 stars, visible in a small telescope. The main star is a yellow dwarf, like our Sun. The second star is a red dwarf 7 stars.

Iota of Cassiopeia is a white double star of 5 stars. has a satellite of 8 stars. In a telescope from 100 mm with a high magnification, you can see the third satellite near the main star, the brightness of the satellite is 7 stars.

As stated at the very beginning of the article, the constellation Cassiopeia is rich in open star clusters.

M 52 (NGC 7654)- the most famous open cluster in Cassiopeia. It can be observed with binoculars. In a large telescope, you can see a rich scattering of small stars. In the west, this cluster is called Cassiopeia Salt-and-Pepper. Finding the cluster is quite easy, it is located on a straight line of Shedar and Kaph stars at a distance from Kaph equal to the distance between these stars.

Monsieur M 103 (NGC 581)- another open star cluster from the catalog. It is located near the star Rukbah. Through a telescope, the cluster looks like a triangle of stars and resembles a Christmas tree; because of this similarity, some astronomers call this star cluster the Little Christmas Tree.

Notice the star cluster NGC 7789. It is located between Rho Cassiopeia and Sigma Cassiopeia. The telescope shows many small stars, as if swirling into a whirlpool. Therefore, in the west, this cluster is called the "White Rose" or "Caroline Rose". Because this cluster was discovered by Caroline Herschel in 1783. Some Russian astronomers call this cluster "Plate". Be sure to look at the star cluster NGC 7789 in a large telescope, you will not regret it.

For lovers of sidewalk astronomy, we can recommend such a star cluster as Owl NGC 457. In a small telescope with low magnification, this open star cluster appears before us in the form of an owl with burning eyes and outstretched wings. This star cluster is very spectacular and will leave a deep impression on curious passers-by who look through your telescope.

Don't miss the compact star cluster NGC 654, as well as a larger star cluster NGC 663.

For lovers of astrophotography, the constellation Cassiopeia has two rather interesting nebulae in store. These are the Bubble Nebula and the Pacman Nebula.

The Bubble Nebula (NGC 7635) is an emission nebula formed due to the stellar wind of the massive star BD+602522. In the pictures, the nebula is indeed visible as an inflated bubble, but slightly deformed on one side due to the resistance of the molecular cloud, which is also clearly visible in the photographs. In large telescopes with special Deep-sky filters, you can just notice this part of the "Bubble".

- named after the hero-kolobok from the Pac-Man computer game of the same name. Indeed, in photographs, the nebula resembles a bun with an open mouth. A young star cluster is immersed in the nebula IC 1590. The stars in this cluster formed from the gas of the Pac-Man Nebula. The distance to this cradle of stars is 10,000 St. years.

Constellation Cassiopeia (Cassiopeia, Cas)

Prepared by: website
10-10-2013

Perhaps the second most recognizable circumpolar constellation after the "bucket" of Ursa Major is Cassiopeia, whose stars form a figure similar to the Latin letter "W". But if we take into account the star of the fourth magnitude κ Cassiopeia, the figure of the constellation also becomes like ... a small bucket!

The constellation is named after Cassiopeia Greek mythology wife of the Ethiopian king Cepheus (Cepheus) and mother of Andromeda. According to one version of the myth, Cassiopeia was tied to a chair for her boasting, sitting on which she was doomed to circle around the North Pole. celestial sphere turning head down.

The constellation Cassiopeia is one of the 48 constellations mentioned by Ptolemy in his catalog of the starry sky, and therefore is one of the oldest constellations of the starry sky. The main asterism of Cassiopeia is formed by 5 stars of the 2nd and 3rd magnitude, forming a "W"-shaped figure of the constellation. Due to their brightness, they are clearly visible in the sky, even in urban lighting conditions.

In the sky, the constellation Cassiopeia borders on such constellations as Cepheus, Giraffe, Lizard, Andromeda, Perseus and is available for observation in the latitude range from + 90 ° north latitude. down to -20° S On the territory of Russia is unset constellation.

An easy way to find Cassiopeia in the sky

Before proceeding to the description of the sights of this constellation, we will help novice astronomers find it in the sky. To do this, we will first find the "bucket" of the Big Dipper, then the North Star. Now let's draw a mental line from the star Aliot (ε Ursa Major) through the North Star further to the same angular segment (see the figure above). Here we can easily find the characteristic "W"-shaped figure of the constellation Cassiopeia.

Cassiopeia on a modern map of the starry sky

Let's take a closer look at the main stars of this constellation. Let's start with the star β Cassiopeia, which is called Kaph. The name of the star, apparently, came from the letter Arabic alphabet"Kaf", since its outline is very similar to the figure of this constellation. Kaph is a yellow giant of spectral class F. The brilliance of the star is +2.28. led. However, it is not constant and varies from +2.25 to +2.31 stars. led. with a period of 2.5 hours. Before us is a variable star of the δ Scuti type.

Now let's move on to the star α Cassiopeia, called Shedar. Being at a distance of 230 light years from the Earth, this star, which is an orange giant, is visible as a luminary +2.23 stars. vel., while the luminosity of Shedar is 500 times greater than the luminosity of our Sun!

At one time, the Shedar star was also considered a variable, but since the 19th century there have been no signs of its variability.

Owners of small telescopes will be interested to take a look at the star η Cassiopeia - a beautiful double star, 19.4 light-years away from us. The main yellow star +3.34 stars. led. almost the same spectral type as our Sun, therefore, observing it even with the naked eye, you can imagine what our Sun looks like from a distance of 19 light years. Near the main yellow star, at an angular distance of 13 ", the second component of this binary system is noticeable - a colder orange star + 7.51 mag.

Next, let's get acquainted with the star γ Cassiopeia, which is called Navi (Navi, from English navigation - navigation). This name was given to the star by the American astronaut Gus Grissom, because. γ Cassiopeia has been a navigational star in a number of space missions. And, due to its physical features, this star is of undoubted interest. So, in 1937, its brilliance was equal to +2.2 magnitude. However, by 1940 it had weakened to +3.4 stars. led. In 1949, γ Cassiopeia increased in brightness to +2.9 stars. great., and by 1965 it became even brighter (+2.7 stars. great.). Today, the brightness of this star is +2.15 stars. led. and she is the brightest star in the constellation. The reason for the brightness instability is the very rapid rotation of this star around its axis, as a result of which it is strongly oblate from the poles. Given the high luminosity of the star, γ Cassiopeia loses the stellar matter accumulating in its equatorial zone, which forms a disk around it, which, apparently, affects changes in the apparent brightness of the star.

We also add that γ Cassiopeia is a spectral binary star with a period of revolution of the components around a common center of gravity equal to 204 days. The estimated mass of the satellite roughly corresponds to our Sun.

Now let's turn our attention to the next star of Cassiopeia's "zigzag" - Rukba (δ Cassiopeia), which in Arabic means "knee". Rukba is an eclipsing variable star with a period of 759 days. The apparent brilliance of a star varies within insignificant and imperceptible limits for the human eye - from +2.68 to +2.74 stars. led. Rukba is 99 light years away from Earth.

The last star of the "W"-shaped figure of the constellation is the star ε. She also has a name - Seguin. The star Seguin is 441 light years away from us and in our sky its brightness is +3.38 stars. led. Before us is a white-blue giant with a luminosity exceeding the luminosity of the Sun by 720 times!

Now that we have met the main stars of the constellation, let's move on to other objects that attract the attention of astronomy lovers. First of all, I would like to draw attention to one more variable star in this constellation, designated by the Greek letter ρ. On dark nights, it can be easily found with the naked eye south of the star Kaph (β Cassiopeia) as a star of about +4.5 stars. led. What is interesting about this star? Despite its mediocre brilliance in the earth's sky, we have a real yellow hypergiant in front of us, it is removed from us at a distance estimated at 11,700 - 15,300 light years. ρ Cassiopeia surpasses the Sun in radius by 400 - 500 times, and in luminosity - by about 500,000 times!

Animation of processes occurring with ρ Cassiopeia

Ρ Cassiopeia belongs to the so-called semi-regular variable stars and its brightness varies between +4.4 and +5.1 stars. great, but in 1946 it weakened to +6 stars. The interval between individual brightness maxima is about 100 days, but no clear periodicity of the star's brightness fluctuations has been recorded. Near the maximum, the spectrum of ρ of Cassiopeia corresponds to the F8 class, while it seems to be a reddish star, which is not typical for this spectral class. Sometimes (during brightness fluctuations) the spectral class of a star changes from F8 to K5, and in the year mentioned in 1946 it even became M5, which corresponds to red stars (by the way, ρ Cassiopeia seems to many observers to be a red star). In any case, this star should be taken under observation and its brightness determined from night to night, since its unexpected changes are always possible, including weakening to 6 stars. led. And such observations, of course, can also have scientific value.

Search map of ρ Cassiopeia and comparison stars

Now information for those who are armed with binoculars or a telescope and are ready to take a walk through the brightest star clusters of the constellation. Let's start with the open star cluster M52 (NGC 7654), located to the west of the star β Cassiopeia. To search for this object, we will arm ourselves with binoculars and draw a mental line from the star α Cassiopeia through the star β Cassiopeia further at approximately the same angular distance. Here, against the background of placers of stars of the Milky Way, this small open star cluster is located, consisting of two yellowish stars +7.77 and +8.22 stars. Vel., as well as stars of the 11th magnitude. In binoculars, M52 will seem more like a small hazy speck, but in telescopes with an objective diameter of at least 100 mm, you can see individual faint stars of this open star cluster in the form of the letter "V".

Another open star cluster in the constellation Cassiopeia, visible with binoculars, is M103, located next to the star δ Cassiopeia. M103 is easy to spot with binoculars and is visible as a compact glowing hazy speck. It is worth noting that it is better to get acquainted with M103 with the help of binoculars, since due to the small number of stars included in the cluster, when observed through a telescope, it "dissolves" against the background of surrounding star placers. But on the other hand, the telescope will help you make out the faint stars of this cluster, which is 8000 light-years away from us.

There are other open star clusters in the constellation Cassiopeia, such as NGC 659, NGC 663, NGC 654, and NGC 457, more than 9000 light-years away from us and including about a hundred stars. Against the background of this cluster, the star φ Cassiopeia is visible, but it has nothing to do with NGC 457.

In conditions of urban illumination, in which the observation of deep space objects becomes difficult, we can recommend observing the Queen’s Kite asterism, which is perfectly visible through binoculars. The asterism is located slightly to the east of the star δ Cassiopeia, and the brightest star of this asterism is the star χ Cassiopeia (magnitude +4.7 magnitude). The brightness of the remaining stars included in the asterism is 6 - 7 stars. size. And in its form, asterism is similar to a kite. And the larger the lens diameter of your optical instrument and the darker the sky, the more star placers you can see in this corner of the starry sky.

Queen's Kite asterism search chart

Of course, the story of Cassiopeia cannot be completed without mentioning the supernova observed by the famous astronomer Tycho Brahe in 1572. This supernova is part of 8 supernovae about which historical information has been preserved. So, November 1572 was going on ... “One evening,” writes Tycho Brahe, “when I, as usual, examined the sky, the appearance of which was familiar to me, I, to my indescribable surprise, saw near the zenith in Cassiopeia a bright star of extraordinary magnitude.Struck by the discovery, I did not know whether to believe my own eyes.

The new star had no tail, no nebula surrounded it, it was in every respect like other stars of the first magnitude ... In terms of brilliance, it could only be compared with Venus, when this latter is at a close distance from the Earth. People gifted with good eyesight could distinguish this star when clear sky day, even at noon. At night, when the sky was cloudy, when other stars were hidden, the new star remained visible through rather thick clouds.

Starting from December 1572, its brilliance began to decrease ... Transition from 5 stars. led. to 6m led. occurred between December 1573 and February 1574. The next month the new star disappeared, having flashed for seventeen months and leaving no trace visible to the naked eye."

In 1952, at the site of the explosion of this supernova, astronomers found a source of radio emission, and 8 years later, its remnant was also found in the optical range.

Cassiopeia in the northeast sky at midnight on July 10, 2005

In preparing the material, the following sources were used: the wikipedia site, the book by F.Yu. Siegel "Treasures of the Starry Sky".

One of the most recognizable constellations in the northern hemisphere of the sky - Cassiopeia. Many of you have noticed in the circumpolar region a silhouette of bright stars in the form of the letter M or W, and so this is the famous asterism in the constellation Cassiopeia. The constellation lies on the strip of the Milky Way, as a result of which it is fraught with many open star clusters and more. Let's reveal all the secrets of this section of the celestial sphere.

Legend and history

The constellation got its name from one beautiful Greek legend. A long time ago lived the king of Ethiopia, Cepheus. He had a daughter, Andromeda, and a beloved wife, Cassiopeia. The wife often boasted of her beauty to the sea nymphs and one day they complained to Poseidon (God of the seas) about this. Poseidon, as punishment for boasting, sent the huge sea monster Kita to Ethiopia. From time to time, the whale swam to the shore and ate people and animals. Cepheus was very frightened and sent messengers to the oracle Zeus in Libya for help, hoping to get at least information on how to get rid of the monster.

The decision from the oracle was as follows - the Whale must eat Andromeda, and then he will leave the other inhabitants alone. King Cepheus resisted for a long time and did not want to give his daughter away, but the people forced him to do it. Andromeda was chained to a rock and left.

Fortunately, it was at this time that Perseus, the son of Zeus, flew over Ethiopia, he was returning home after defeating Medusa. Perseus really liked the chained girl and he decided to save the beauty at all costs. When the whale swam out of the sea, Perseus entered into battle with the enemy. The battle lasted for several hours, but in the end Perseus won and freed Andromeda.

In memory of such a valiant heroic deed, all the characters were placed in heaven. Therefore, in our time in the sky you can see the constellations, and.

Characteristics

Latin name	Cassiopeia
Reduction	Cas
Square	598 sq. degrees (25th place)
right ascension	From 22 h 52 m to 3 h 25 m
declination	+46° to +77°
The brightest stars< 3 m)	Shedar (α Cas)- 2.24 m Kaf (β Cas)- 2.27 m Navi (γ Cas)- 2.47 m Rukba (δ Cas)- 2.68 m
Number of stars brighter than 6 m	90
meteor showers	-
neighboring constellations
constellation visibility	+90° to −13°
Hemisphere	Northern
Time for observation on the territory Belarus, Russia and Ukraine	Autumn

The most interesting objects to observe in the constellation Cassiopeia

1. Open star cluster M 52 (NGC 7654)

Very saturated and dense open cluster M52 includes about 100 stars with a total brightness of 6.9 m and angular dimensions of 16 ′. It is clearly distinguishable even with binoculars or the simplest amateur telescope.

A closer look at the cluster reveals several cool orange stars. At high magnifications through a telescope M52 fully resolved into individual stars. But count exact number stars are unlikely to come out, do not forget that the density of stars is much higher in the Milky Way strip.

open cluster M52 lies almost on the border with the constellation Cepheus, next to the Bubble emission nebula ( NGC 7635), which can be seen in the photo above in the upper right corner. I recommend laying the route from the bright star Kaf, the brightness of which is 2.27 m (shown below red arrows).

2. Diffuse Bubble Nebula (NGC 7635, C 11)

Near M52 located (emission) nebula NGC 7635(or "Bubble"). It is listed under the catalog number. C 11. The cloud of ionized gas has a brightness of about 10th magnitude and an apparent size of 15.0' × 8.0'. Unfortunately, more often the nebula can be captured on a camera than seen with one's own eyes in the eyepiece of a telescope, due to the low surface brightness and relatively large size.

Higher on the atlas green arrows showed the location of the diplomatic "Bubble".

3. A pair of open star clusters NGC 7788 and NGC 7790

Nice couple of small open clusters NGC 7788 and NGC 7790 only visually it seems that they are separated by a distance of several light years. In fact, this is an optical illusion and the clusters do not interact with each other in any way. The angular distance between the clusters is slightly more than 10′. Thus, in a wide-angle eyepiece, you can clearly see them simultaneously in the same field of view.

It's interesting that NGC 7790 brighter, larger and was discovered almost 40 years before its nearest neighbor NGC 7788. The brightness of the first cluster is 8.5 m , the angular size is 5′. Brightness same NGC 7788- 9.4 m, and the angular size - 4 ′.

We start the search from the star Kaf ( βCas) and slightly shift the telescope tube in a northeasterly direction. On the star map above blue arrows marked the direction to a pair of clusters.

4. Open star cluster NGC 7789

Large, beautiful and rich open cluster NGC 7789 fascinates with its appearance even when meeting with binoculars. About 150 dim stars give a total brightness of about 6.7 m and scattered "grains" over an area of ​​25 ′. The photo above shows how many other background stars are in this region of the sky, and when you look through binoculars or a telescope, their number increases even more. My head is spinning from what I see.

Cluster NGC 7789 some sources call the Rosa Carolina cluster in honor of the German discoverer Caroline Herschel. The cluster has been removed from us at a distance of 8000 light years.

We start the search from the already familiar star Kaf or βCas and move the telescope tube in the direction indicated red arrows on the atlas.

5. Diffuse nebula NGC 281 + open cluster IC 1590

Immediately it is worth clarifying some confusion in the names of the nebula and the cluster. In some textbooks you can find NGC 281 as an open star cluster with a nebula, while other sources are clearly divided into two deep skys: NGC 281- this is an emission nebula, that is, a region of ionized hydrogen in which processes of active star formation and IC 1590- a small but very open cluster.

The distance to a pair of deep-sky objects is approximately 10 thousand light years. The total dimensions of the nebula are 35.0' × 30.0'. Brightness - about 7 m . By the way, often NGC 281 called the Pac-Man Nebula, after the character in the arcade game of the same name.

And again, lovers of astrophotography rejoice, with a telescope I was able to distinguish only an open cluster IC 1590 in the form of several bright stars, I did not notice any signs of nebula. How are you doing with Pac-Man? Share in the comments after reviewing the constellation.

The starting point for the desired pair of deep-sky objects will be the brightest star of the constellation Shedar or αCas gloss 2.24 m .

6-7. Pair of dwarf galaxies NGC 147 (C 17) and NGC 185 (C 18)

Next on the list of interesting deep skys in the constellation Cassiopeia are two dwarf galaxies. NGC 147 and NGC 185. The angular distance between them is slightly less than 1°. Galaxies do not interact with each other in any way.

NGC 147- a dwarf spheroidal galaxy, that is, small in size, almost spherical in shape and low surface brightness. At the same time, its total brightness is 9.3 m, and the angular dimensions are 13.2′ × 7.8′. By the way, it belongs to the Local Group of Galaxies and is a satellite of the famous Andromeda Nebula galaxy from the constellation.

NGC 185 is a dwarf elliptical galaxy. Also belongs to the Local Group of galaxies. Brightness - 9.2 m , angular dimensions - 14' × 12'. The 10-inch telescope looks much brighter, with a brightly defined core.

And again we find the bright star Shedar and move to the side Andromedae, after more than 7 degrees, bypassing several bright stars, you can distinguish 2 blurry hazy spots. Don't miss them, they are especially visible with peripheral vision, against the background of sharp stars.

8. Open star cluster NGC 457 (C 13)

NGC 457 or cluster Owl(and sometimes a cluster Dragonfly) is a very famous open cluster among observant astronomers. Indeed, it is very easy to imagine according to the contours of the stars: two bright eyes, wings, tail and body.

The apparent stellar magnitude of the cluster is 6.4 m, the apparent dimensions are 20′. Under ideal weather conditions, it can be seen even with the naked eye. It is best to observe with binoculars or an optical telescope finder. One of the favorite open clusters for astrophotographers.

In the night sky NGC 457 very easy to find, below on the map with colored arrows I offer several options (there, by the way, there is another cluster nearby NGC 436):

9. Open star cluster NGC 436

Compared to the previous NGC 457) cluster NGC 436 lost in the background of other stars. It can only be seen with binoculars. It includes about 25 stars of 12 - 14 magnitudes with a total brightness of 8.8 m. Visible dimensions - 5'.

Usually, NGC 436 observed in tandem with "Owl". In the photo below, you can notice the difference in size and brightness of the two neighboring clusters.

Open clusters NGC 436 (right) and NGC 457 (left)

10. Open star cluster M 103 (NGC 581)

Another open cluster M103, which fell into the Messier catalog, although it was discovered by Pierre Mechain. It is removed from us by 8 thousand light years and consists of 20 - 25 stars of different luminosity. Even in the image, shades of stars from blue to orange are clearly visible.

The brightness of the cluster is 7.4 m , the visible dimensions are 6'. I recommend studying the constellation through the eyepiece of a telescope at a low magnification; for 15x binoculars, the dimensions are still too small.

We find the bright star Rukba ( δCas) and move the pipe slightly eastward. Close to M103 there are three more clusters ( NGC 654, NGC 659, NGC 663), which we will discuss below.

11. Open star cluster NGC 654

I immediately apologize for the quality of the image, I simply did not find the best on the Internet, if you have a better one and you can publish it - write to the mail or in the comments.

Cluster moved away a little NGC 654 from a pack of others, however, no less interesting. It can be seen even with binoculars, but due to the small angular dimensions (6 ′), it is better to use a telescope. The brightness of the cluster is 6.5 m.

Stars in a cluster NGC 654 very scattered around the perimeter, and given that you can see hundreds of other stars in the background, you generally get lost in the integrity of the picture you see at first. But let your eye get used to it and "everything will fall into place." Start your search from the Rukba star, and through M103 you can get to the desired cluster NGC 654.

12. Open star cluster NGC 659

Another representative of a not very bright (luminosity - 7.9 m), but well distinguished from other stars, is an open cluster NGC 659. The number of stars in the cluster is 40. The brightest of them has a magnitude of 10m. The total dimensions of the cluster are 6′.

Near NGC 659, at a distance of a little more than 30 ′, one more cluster can be found - NGC 663.

13. Open star cluster NGC 663 (C 10)

The largest and most populous open cluster in the local group - NGC 663. It covers about 80 stars with a total brightness of 7.1 m. Visible dimensions - 15'. You can see it well even with binoculars.

The cluster has very interesting shape: the brightest stars outline the contours of a horseshoe, in the middle of which there is not a single star. The stars on the periphery merge with the background.

When using an ultra-wide-angle eyepiece and a low magnification (up to 50x), it is possible to cover NGC 659 and NGC 663. Below is a snapshot of a pair of clusters against the backdrop of bright stars.

14. A pair of diffuse nebulae "Heart" (IC 1805) and "Soul" (IC 1848)

So that you immediately understand the cosmic scope of the nebulae IC 1805(Heart) and IC 1848(Soul), imagine in the image above the angular distance from the left edge of one nebula to the right edge of the other is 2.5°. That is, it is like 50 diameters of the full moon or almost 200 diameters of the planet Jupiter. And this raises the question: Are these nebulae visible to the naked eye?? No.

Despite the apparent stellar magnitude of 6.5 m for each of the nebulae, they are separately visible either under the most favorable weather conditions hundreds of kilometers from cities using special light filters or during astrophotography. The human eye, unfortunately, cannot distinguish such dim objects, but a digital camera can even in color.

In the "Heart" nebula, a separate section of interstellar matter has its own serial number in the New General Catalog - NGC 896.

Both nebulae are about 7500 light-years away from us; they are clouds of ionized hydrogen (plasma) that emit in the visible range of the spectrum. In books on astronomy, you can find images in the infrared range, for example, the following:

"Soul" (left) and "Heart" (right) in infrared

I recommend looking for nebulae from the extreme bright star of asterism εCas, and further towards the constellation, you will notice clouds of ionized gas. There, by the way, between them there is a good clue in the form of an open cluster NGC 1027. Another option is to start searching from clusters Hi-Ash Perseus.

15. Open star cluster NGC 1027

Between hid a handful of stars in the form of a cluster NGC 1027. The brightness of the cluster is 6.7 m , and the apparent angular dimensions are 15'. Thus, it can be seen both with binoculars and with the most budgetary telescope. Please note that in the image above, the Heart Nebula is visible against the background of the cluster ( IC 1805).

In fact, when you observe this cluster with binoculars or a telescope at low magnifications, you will not notice any nebulae in the background. It is necessary to use an additional special narrow-band light filter, which will add contrast to the nebula and blacken the cosmic background.

On the other side of the W or M asterism, there are many equally interesting deep-sky objects. Time to get to know them.

16. Open star cluster NGC 637

NGC 637- small (visible dimensions only 3′) and dim (brightness - 8.2 m) open cluster. Consists of 15 stars, which are very tightly gravitationally bound. Against the background of other stars, they are distinguished by greater brightness and size of individual stars. In a telescope, even at 80x magnification, the cluster is completely placed in the field of view of the eyepiece.

Starting from a star εCas, the extreme star of the asterism, and, bypassing the star of the 5th magnitude, you will meet the desired deep sky NGC 637.

17. Open star cluster NGC 609

Continuing the route from the star εCas through the cluster NGC 637, you will encounter another open cluster NGC 609. It's okay if you can't find it the first time. The brightness of the cluster is 11 m , and the dimensions are 3′.

In fact, the cluster is larger than the previous one and more saturated. It has about 40 stars. But it is much further away from us and it will not be easy to notice it in the canvas of other stars. I recommend looking in a telescope with a main mirror diameter of 200 millimeters (or 8 inches).

In the image below, the difference in brightness between the two clusters is almost indistinguishable:

18. Open star cluster NGC 559

At some distance from the previous ones, or rather at 1.5 °, there is another small open cluster NGC 559. According to some estimates, it consists of 40 stars of 12 - 16 magnitudes with a total brightness of 9.5 m and dimensions of 7 ′. The cluster is surrounded by (optically) a dozen brighter stars from 6 to 8 magnitudes.

On the star map above blue arrows showed the direction to deep-sky.

The central part of the constellation has not yet been discovered Cassiopeia. We move towards it and get acquainted with each deep-sky object personally.

19. Open star cluster NGC 381

Between the stars Navi and Rukba is a small cluster of very distant stars. The brightness of each star does not exceed magnitude 16, while the total apparent magnitude is 9.3 m. Dimensions - 7 ′, but it is very difficult to separate the cluster from other stars; The image above is proof of that.

Most deep-sky objects in the central region of the constellation are best found by starting from the star Navi or cafe. They are bright (about 2.4 m), visible to the naked eye, they are easy to find with an optical finder, and the desired clusters are not far from them.

Central part of the constellation Cassiopeia

20. Open star cluster NGC 225

Very beautiful and bright open cluster NGC 225 with nebula in the background. Consists of 20 stars from 9 to 11 magnitudes. Someone sees the letter W, like the asterism of the same name in the constellation, for others it is a stretched spiral spring.

The brightness of the cluster is 7 m , and the angular dimensions are 15′ (in other sources you can find the number 12).

On the atlas above from the star Navi green arrows indicated the direction to the cluster.

21. Pair of open clusters NGC 133 and NGC 146

This pair of clusters is probably the most difficult to find in the sky. An excellent guide will be a bright star of the 4th magnitude κCas.

NGC 133- an open cluster with a brightness of 9.4 m and an angular size of 3'.

NGC 146- an open cluster, the brightness of which is 9.1 m, and the apparent dimensions are 5 ′.

Each cluster contains 25 - 30 stars from 15 to 18 magnitudes. Gravitationally, the clusters are not connected in any way, they are removed from solar system at a distance of approximately 15,000 light years.

22. Open star cluster NGC 189

open cluster NGC 189 contains 2 groups of stars: blue hot B and A, and already cooling, surviving stars of the spectral class G and K.

The brightness of the cluster is 8.8 m , and the angular dimensions are 5'.

The search should start from the Navi star, after finding a large cluster NGC 225 and from it already move a little to the west to detect NGC 189. On the map above, green arrows indicated the direction immediately from the star HIP 4151 to the desired deep-sky object.

23. Open star cluster NGC 103

Clustered M103 we met earlier, now we have to learn about the open cluster NGC 103. Its brightness is noticeably lower, only 9.8 m. Consists of a dozen stars of 12 - 14 magnitude with a total area of ​​​​5 ′.

It is desirable to find all clusters in this central group one after another, for example, they found NGC 189, then follow to NGC 103. Nearby, although there are several stars of 6th magnitude, it will be problematic to immediately point the finder at them. You can also try to plot a route from the star Kaf ( βCas), from which we previously found clusters of the type NGC 7788 and NGC 7790.

24. Open star cluster NGC 129

And finally, the last and largest open cluster in the constellation Cassiopeia - NGC 129. Against the backdrop of previous clusters NGC 129 really has impressive dimensions (12 ′) and high brightness (6.5 m).

The bright star at the bottom of the image is a binary star with a brightness of 6 m .

The route can be laid from the star Navi(as indicated by the blue arrows on the star map above) and from the star cafe. Both options are optimal and easy.

Multiple star systems

25.1 Double star η Cas

ηCas or Cassiopeia - a double star, the components of which are: the main star is a yellow giant with a brightness of 3.7 m, and its companion is a red cold star with a brightness of 7.4 m. The angular distance between the stars is 12.2″. The orbital period of the satellite around the main star is 526 years. Removed from the Sun at a distance of 20 light years.

25.2 Double star σ Cas

σ Cas or Sigma Cassiopeia - a double star, which consists of a main component with a brightness of 5 m, and its companion with a brightness of 7.1 m. The distance between the stars is 3″.

Search double stars Eta and Sigma Cassiopeiae

Our space view of the constellation Cassiopeia came to an end. Well, are you impressed? What did I miss or not note? What can be added or corrected?