Arcturus 28 stars

The positions of cygnus, lyra and aquila.

Cygnus

Cygnus is one of the northern constellations. The Latin name of Cygnus is cygnus, abbreviated as cyg. It means swan. At 20 o'clock on September 25 every year, the swan constellation rises to the sky. Summer and autumn are the best time to observe Cygnus. Interestingly, the rise and fall of Cygnus is really like a flying swan: it rises obliquely from the northeast to the sky, and when it reaches the zenith, its head points to the west. When it moves to the northwest, it turns head down, tail up and disappears on the horizon.

General introduction

Cygnus is completely immersed in the white Milky Way, standing on both sides of the Milky Way with Aquila and Lyra. The three main stars (alpha star) of these three constellations form a big triangle (summer triangle). Cygnus is located at 20: 30 right ascension and 44 declination. The area is 804 square degrees. There are 19 1 stars in the constellation with visual magnitude greater than 6, and 22 of them have brightness greater than 4. Therefore, in the summer night sky, although the Milky Way is like a veil and full of stars, it is not difficult to find Cygnus, which can still shine in the Milky Way.

Alpha cygnus

It is a white first-class star, which is 1500 light years away from us. It is a Supergiant star, which actually radiates 5000 times more light than the sun. Around this star, there is an encirclement formed by a gas cloud expanding at a speed of 100 km per second. In the next 8300 years, Cygnus alpha will be the brightest star closest to the North Pole, only 6.6 degrees away from the North Pole of the celestial sphere. At that time, it will become the "North Star".

Lyra

Lyra, one of the northern constellations. Center position: right ascension 18: 50, declination 36. The area is about 286 square degrees. Between Draco, Hercules and Cygnus. There are 53 stars in the constellation with visual magnitude greater than 6, and 8 of them have visual magnitude greater than 4. On a summer night, there is a very bright star on the west bank of the Milky Way. Together with some small stars around, Lyra is formed.

Among the four diamond-shaped stars, Qin Tian's D star "Yitai-1" in the northeast corner is a distant binary star, and the two stars are not related. They are optical binary stars, one is a red giant star with a brightness of 4.3, and the other is a blue and white star with a brightness of 5.6, which can be distinguished by binoculars. When the weather is fine, they can be vaguely distinguished by the naked eye. In addition, not far from the northeast of Vega, there is a Qin Tian E-star "Weaver Girl II", which is a twin star, also known as a four-star. People with good eyesight can see a pair of magnitude 5 stars with binoculars. If you use a 6-to 7.5-caliber telescope, you can see that these two stars are close binaries at high magnification, and the wider pair is 5.0 and 6. 1 respectively, with a period of 65438. The other pair is 5.2 and 5.5, the orbital period is 600 years, and the four stars are about 130 light-years away from the earth.

Relevant astronomical data

Vega's apparent magnitude is 0.05m, which is the fifth brightest star in the whole day. It is 26 light years away, and it is the first star whose distance has been accurately measured by astronomers. Remember we said that Polaris always on duty by turns due to precession. 12000, Vega will be the North Star at that time. At that time, Lila would definitely be more important than now. The brightest star in Lyra is Lyra A-"vega", also known as Vega, whose English name comes from Arabic "swooping vulture". Its brightness is 0.03, blue and white, 25 light-years away from the Earth, and it is the fifth brightest star in the whole day, ranking second in the northern celestial sphere, second only to the arcturus of the Capricorn, and its brightness is 25 times that of the sun. There are also some dark stars around Vega, among which a small diamond in the southeast is obvious, which is composed of four stars below the second class. It is said that it is a shuttle used by the weaver girl to weave cloth. Among them, the Qin Tian B (sheliak) located in the southwest corner is a binary star, and its main star is also an eclipse star, with a brightness of 3.3-4.4 and a period of 12 days and 22 hours. It consists of two stars in close proximity, rotating each other and spewing gas. The two stars are squeezed by gravity and constantly change light. It is not clear when the food starts and ends. There are other similar variables in the universe, called "Lyra B variable". Compared with Lyra G (brightness 3.24) and Lyra K (brightness 4.33), its distant companion star of 7.2 can be seen with a small telescope.

Tianying constellation

Eagle is one of the zodiac signs. The area is about 652 square degrees. Located in the south of Lyra and the north of Sagittarius, most of them are in the Milky Way. There are 87 stars in the constellation whose visual magnitude is brighter than 6, of which 13 is brighter than 4.

Introduction to aquila

Center position: right ascension 19: 40, declination 3. Aquila, abbreviated as Aql in Latin, is located in the south of Cygnus and Lyra. Among them, there are 70 brighter than Chang 'e VI, 6 on Chang 'e IV and 5 on Chang 'e III. The first bright star, Tianying α, is the familiar Altair (also known as Hegu II). It is a white main sequence star with brightness of 0.77, which is 16 light years away from us. It is also a fast-rotating star, rotating once in about 7 hours, while the average rotation period of the sun is about 17 days. In China's traditional star officials, Eagle is equivalent to drums, right flags, heavenly forks and Arabian nights. Ancient Arabs regarded Aquila and Lyra as two eagles. Europeans call Alpha Lyra the "Flying Eagle" and Alpha Lyra the "Falling Eagle". Aquila is a region with many new stars. 19 18 there was a new star, aquila V603, whose brightness was second only to Sirius, the brightest star in the whole day.

Landlord, I'm a little curious. What do you need the positions of these three constellations for?