LEGEND

The king of Argos Archady had only one daughter Danaya with the extraordinary beauty of herself, she could be compared only to the immortal Goddess, but Archady had been predicted to die of the hand of his grand child - son of Danaya. To avoid such doom Archady build deep down in the ground a palace of stones and bronze and inside of it he closed his daughter. Nobody had the access to it and nobody could see her. Archady did not know that the powerful Zeus had been enchanted by his daughter and transforming into golden rain Zeus reached to Danaya. She became his wife and gave a birth to his son, called Perseus.


Perseus grew up under the care of his loving mother. He became a very cheerful young boy and his laughter spread at far away. One day Archady heard it and immediately, when he saw his daughter and his grand son. He remembered of the fortune -telling of the oracle but could not dare to kill Zeus son. Because of this he ordered to make a huge wooden chest was thrown in the sea.

Days and nights the chest was,carried by the wild waves of the sea. At last the chest was thrown out on the coast of Serifus island in the Aegean sea. They were found by the brother of king Polidekt -Dicktus. The king them and they were visitors in his splendid greeted palace. Perseus grew as the strongest and the most courage youth on the island. But Polidekt decided to take a revenge of Perseus' mother because she refused become his wife. He called Perseus and assigned him to bring the head of Gorgona Meduza.Perseus accepted the challenge.

Gorgonas were terrible creatures. They were so honified that every one who dared to look them immediately had been turned into a stone. The gorgonas kept they territory absolutely careful. If anybody stepped in their country had been torn to pieces and his blood had been drunk by the gorgonas.
The task given by Polidect was hardly doing but Perseus did go. Zeus sent his favourite daughter Athens and Hermus to protect Perseus. Athens gave him a shield and Hermus - a sword. Perseus could beat shining any body with these arms.

Perseus went to his long journey. He passed by countries, towns and villages, then he reached a dark country. Three sisters had lived there they were called grai. They were very ugly and had one eye only, which they passed, through one another. When one of the sisters had it the other two were behind Perseus waited till the eye was in the hands of one of the sisters and grabbed it. Perseus understood that the sisters knew the way to the gorgonas but they kept it in deep secret. But Perseus took the truth out from them. The sisters showed him the way to the Gorgona's country. When he went, he passed through the nymphs. They gave him three gifts: the helm of Hades, which makes every body who, puts it on, invincible, flying sandals and magic bag. Perseus thanked and flew away to the island of the Gorgonas.
When Perseus reached the island he saw a bright spot - those were the three sisters - Meduza, Steyno and Evraylla. They stood there and their bodies shined upon then Sun. Perseus, was ready to cut off the head of Meduza but he didn't know who she was. They looked alike (three drops of water) very much. But only Meduza could be killed. In this very difficult moment when a deadly danger was over this head Hermes who pointed Meduza helped Perseus. Before she her eyes Perseus managed to cut her head off and without looking her, he put her the head in the bag and with his invisible helm he flew away in the air.
Perseus reached the West Side of the Earth where. Atlas was holding the sky. In the Atlas's garden there was a magic tree with garden apples. The god's Temida predicted Atlas that the Zeus's son world grabs the apples. So Atlas kept them very striating and when Perseus appeared Atlas didn't invited him in his home.

The constellation Perseus is almost in the Milky Way galaxy, but because of the large amount of bright stars it is well outlined on the white background. The constellations Auriga, Taurus, Andromeda, Aries, Cassiopeia The most appropriate time for watching the Perseus is from November till March. In a bright and moonless night you can see around 90 stars in it with a naked eye. Only 11 are from 2, 3 stars constant and they are matched to from the specific stretched figure. Even if you have a great imagination you can hardly see the body of Perseus, illustrated in the stars maps.

The constellation Perseus has its interesting objects, which can be well seen with a naked eye. On the very first place is a star ? Per, which orbit is called Algol (devil). Most probably they have noticed the changing of its brightness through out time. The Algol star is a typical object of star class, called eclipse variable stars. They are physically binary stars. Two of them surround the mass center and they are close to one another. The plain of the orbit passes by Earth. For that reason, when the satellite is in front of the main star her brightness decreases for some time. This is well seen in the Algol star with a naked eye. During the two and half of twenty-four hours Algol is of second magnitude and they are not changing in its brightness. Then during 5 hours its brightness decreases and becomes of third magnitude. Then after another 5 hours the brightness of the star is restored and the appearance is repeated in a severe period. The constellation Perseus has another variable star, which can be seen with a naked eye. This is the star ? Perseus. Its brightness is changes from 3m,2 to 4m,0, but the period is unstable and it is modify from 33 to 55 twenty - four hours.

M 34
Galactic cluster in Perseus
NGC 1039 2h 38m.8 +42? 34'
Basic date: First recorded by Charles Messier in 1764, this loos cluster of stars is just visible to the naked eye nearly midway from Algol to Gamma Andromedae. It lies 1,400 light-years from us according to H.L.Johnson, who measured a dozen stars in the group as outshining visual magnitude 9.0. However, the most brilliant, at 7.3, is a nonmember. M34 is about ?? in extent, but its brighter stars are concentrated in a smaller area.
NGC description: Bright, very large cluster, little compressed, of scattered 9th -magnitude stars.
Visual appearance: A very fine cluster which 7 x 50 binoculars will resolve quite well. It is so extended that a 4-inch may give a more attractive view than a large telescope would. The main stars form a distorted X. The cluster's second brightest star, magnitude 7,9, is a close visual double with somewhat unequal components 1.4 seconds of are apart. Known as Otto Struve 44, it was discovered by him about 1840 with a 15-inch refractor.
M34 is somewhat more than 2?? due north of the 5th-magnitude star 12 Persei.

M76
Planetary nebula in Perseus
NGC 650-1 1h 38m.8 +51? 19'

Basic date: M76 appears on photographs as a nebulous bar about 1? by ? minutes of are in size, extending Northeast to Southwest, with much fainter patches on either side. Because the ends of the bar are brighter than the middle, William Herschel called M76 a double nebula, which led to the two numbers in the New General Catalogue.
Since its total light is equivalent only to a star of 10th or 11th magnitude, M76 is among the faintest objects in the messier catalogue. The central star of this planetary, in the conmiddle of the bar, is of photographic magnitude 16?. M76 is at a distance of 3,400 light-year.
NGC description: NGC 650 and 651, both very bright, are the preceding and following components of a double nebula.
Visual appearance: A rewarding object in Mallas' 4-inch refractor. M76 is a miniature of the Dumbbell nebula and is more closely described by this name than is M27 in Vulpecula, when both are seen in a small telescope.

In the constellation Perseus around ? Perseus (gamma) is radiant one of the most activity meteor shower - Perseides. It watches from 18.07 to 20.10.2002. It has maximum on 12/13 August when can be watched about 60 meteors.


A lesson of researching and exploring of the variable stars
I. The purpose of observation:
To orientated towards of the place of the constellation on the stellar sky.
To be added and to be relearned the knowledge of the students for the concepts, magnitude variable stars, open clusters
To perfect the skills for working which a mobile stellar map and telescope
To be introduced with some methods of observation of variable and binary stars and clusters.
II. Tasks:
1. To determine the conterminous magnitude on standard square 2 (betta, gamma, zeta Per).
2. To determine the visual brightness of the stars betta (ro or eta) of Perseus in a moment of the exercise by the method of Nailand - Blajko, while using the given in the theoretical notes stars for comparing. To determined the closest to the exercise moment of maximum and minimum brightness of each of them.
3. To find one of the visual binary stars in the moment of observation on the heaven marked in the particular tables of theoretical notes, and to observer with a binocular by paying attention on the attention on the reciprocally position and the color of the components. The same should be done for the open clusters.
4. Make conclusions on the observation:
4.1. Which is the moment of the changing brightness the observed variable stars have reached?
4.2. Identify the components which has been seen, according to the definite colour of the observed binary stars.
III. Necessary means and materials: a mobile map of the North stellar sky, a telescope, a photographic, a camera, a torch and an astronomical almanac.
IV. Basic knowledge: concepts of magnitude; a constellation; a variable star; a binary star; a standard square; brightness and colours of the stars.
V. Way of teaching
1. Introduction: in this night exercise we will make some observations on many and variable object with they different types observing devises according to the necessary of the appropriate observation. Its organization on the autumn allows of almost every task to be done at the same time. The particular object of the described group of object matches with the most interesting and typical one.
2. Theoretical notes:
2.1. Physically variable stars are the stars which change brightness. This changing is due to the inside reason of its own characteristic (physical processes taking place in their entrails and a atmospheres). The changing of the brightness in these stars is due the unstable process in them. For this very reason, they often are called unstable stars. The last are devided to periodical (the brightness is changed unperiodically). The periodic physically variable stars formed two groups: short periodical - with a period of some tenth of twenty - four hours, like the variable star ? Cep and long periodical - with the period of hundred of 24 hours, like the variable Mira (? Cet).
2.2. Eclipsecally variable stars:
This type variable star is consisting of two stars, which round one mass center. The changing of the brightness is due to the reciprocally covering of the components. It is interesting to observe near the minimum of their brightness. For the rest of time they have almost constant brightness. This not refer to the eclipsecally variable with immediate proximity of components ((betta Lyr) which have almost unchanging brightness. A typical object is betta Per (Algol): alpha = 3h 08m 19.9s, delta = 40degrees57minutes 55 sec. - maximum magnitude 2.2, and minimum 3.5. When defying the visual brightness of the variable stars is used the method of Nailand - Blajko. It is to choose sever stable stars near by the observed variable and compared to one another. In the moment of observation we choose three closest and brightness stars - a, b, c. The observed variable star is marked with v. Then we estimate the differs in the brightness between b and v and v and c. For example, for ? Per is better to choose when comparing the following. betta Per - V = 1,8, m = 1,9, F5; delta Per - V=3.03, B5, m=3.10; viPer - V=3.77, F5, m=3.93; pi Per -V=4.70, A5, m=4.62; epsilon Per -V=2.89, B0.5, m=2.96; damma And-V=2.10, K2, m=2.18; alpha Tri-V=3,44, F6, m=3.68; betta Tri -V=3.00,A5, m=3.08
2.3. Binary stars
The reciprocal location of the components is characterized by the different brightness of the stars through the polar coordinates. The shape of the star is circle to 180 degrees. Ones of the most interesting stars are gamma And, alpha =2h01m7, delta =+42deg 10min; tita1Ori and tita2 Ori alpha = 5h33m6, delta = -5deg25min
2.4. Open clusters - this a group of stars formed congestion with unregular shape. The easiest for an observation are h and xi Per; M45, the Pleiades, the Hyades in Tau; M44 in Cnc.

ssssssssssssssssssss M44 sssssssssssssssssssssssssssssssssssssssssssssssss M45

Observation:


On the 10 of August 2002, at 21:30 p. m. UT our group organised an observation the constellation Perseus and the objects in it. The observations carry out in UAO - Silistra (Anna, Radostina, Maria and Marlena). On the standard square 2 we counted 12 stars. The border magnitude is 5.8 m, we observed with telescope Telementor.

The betta Perseus posses to the brilliant stars. The main star is from 3m,8. To 28??6 angle distance from it, is the satellite of 7m,9. The main star glitters with an orange colour and the satellite - with blue colour.
Faraway from ? Perseus star we can see with a naked eye a light spot with an unregular shape. This spot is seen as two open clusters. They are marked with h and ?. They are remarkable because of the largest of the star in them.
The h Perseus open cluster a with magnitude it a grow 4m,3 has a diameter 56 l.y. There have been seen 350 stars. It is on 6200 l. y. from us.
The ? Perseus open clusters with a magnitude integral 4m,3 has a diameter of 77 l. y. There have been seen 300 stars. It is on 6520 l. y. of us.
In the constellation Perseus is the light California nebula. It is lightened by the ? Perseus from 4m,0. The distance to this nebula is 1960 l. y.

We choose following three stars: Alfa Per (1.8 magnitude), Gamma And (2.10 magnitude) and Epsilon Per (2.89 magnitude). According to us during to the observation the star Beta Per is almost to Gamma And. T. i. it is near to own maximum brightness.
We observed with binoculars beta Per. We have some variation to defining on its brightness. Subsequently we accepted that its has blue-white colour. During to the observation on the open cluster h and hi, we defining that they have grey - white colour.
Then we defined the colour of beta Per (blue - white colour) we had watching the main star.

Team: Maria Stojanova Andonova, Radostina Angelova Stefanova, Anna Vasileva Koleva

Leader: Marlena Liubenova

adress: str. "7-th September" 61, P. B. 134 Silistra 7500 Bulgaria

e-mail: nao_ggalilej@mail.bg

Literature:
1. Myths and legends for constellation, Angel Bonov
2. Treasure on the stellar sky, F. Zigel
3. Astronomical almanac, 2002, publishing company "Naturela"