Author: Guo Chaokai
As Tianyu's most anticipated "astronomical blockbuster" in August, the Perseid meteor shower is about to be released shockingly. Astronomical forecasts show that the meteor shower will usher in its maximum period from 21:00 to 24:00 on August 12, Beijing time. At that time, hundreds of meteors are expected to fall into the night sky every hour, making the sky beautiful.
Perseid meteor shower. Photo by Zhan Xiang of Beijing Planetarium issued by China News Service
It is also a great pleasure to enjoy the Perseid meteor shower known as "Saint Laurent's Tears" with family, friends, and friends, and feel the "sweet crit" of summer in the northern hemisphere.
The most beautiful "astronomical blockbuster" in August arrives as scheduled
The Perseid meteor shower, the quadrant meteor shower, and the Gemini meteor shower are also known as the three largest meteor showers in the northern hemisphere. The radiant points of these three meteor showers can rise relatively high in the starry sky of the northern hemisphere, and are suitable for viewing in the northern hemisphere. At the same time, they are stable and appear every year, and there are enough meteors.
The annual activity period of the Perseid meteor shower is from July 17 to August 24, and lasts for more than a month. Generally, the meteor flow reaches a maximum around August 13 each year. Its ZHR (Assumed Radiant Point of Maximum The theoretical value of the hourly flow at the zenith is above 100. The maximum forecast of the Perseid meteor shower this year will appear from 21:00 to 24:00 on August 12, Beijing time. It is suitable for viewing from the evening of August 12 to the early morning of August 13.
Perseid meteor shower. Photo by Zhan Xiang of Beijing Planetarium issued by China News Service
Liu Qian, an associate researcher at the Beijing Planetarium, told a reporter from China News Agency: “Of all the large meteor showers in the northern hemisphere, only the Perseid meteor shower occurs in the warm season, which is suitable for ordinary people to watch casually. Other meteor showers must be prepared for the cold. In addition. Another notable feature of the Perseid meteor shower is the large number of bright, colored fireballs."
Compared with the other two meteor showers, the Perseid meteor shower, which arrives in August every month, is more suitable for astronomers and ordinary people to observe. The quadrant meteor shower and the Gemini meteor shower are relatively difficult to observe because they occur in January and December each year in the cold winter of the northern hemisphere.
Observation strategy: How to "catch" the Perseid meteor shower?
The appearance of the Perseid meteor shower undoubtedly attracted the attention of the general public. Some astronomy enthusiasts have made preparations for observations in order to get a glimpse of the beauty of the Perseid meteor shower.
Cowen, director of the Science Popularization Department of Beijing Planetarium, said that it is best to observe meteors in the suburbs away from city lights, but you must pay attention to safety and familiarize yourself with the venue in advance. In addition, you also need to prevent mosquito bites and keep warm. Observing meteors generally does not require any observing equipment, just with the naked eye. The telescope's visible range is too small, which is not suitable for meteor observation.
"Meteors may appear in any direction in the sky. The field of vision must be wide. Standing up and looking at the meteor will quickly make your neck sore. Sitting or lying down will be more comfortable. If possible, you can prepare chairs and moisture-proof cushions." . Cowen said.
The picture shows the local Perseid meteor shower in Krasnodar, Russia on August 12, 2019 local time. Image source: Visual China
In addition, meteors belonging to the Perseid meteor group have a relatively fast speed of 59 km/s, which is a high-speed meteor group. The time for the meteor itself to traverse the night sky is only a few tenths of a second, which is fleeting. You may exclaim before the meteor disappears before you wish. Some of the brighter meteors will leave a trail for several seconds after flashing.
Liu Qian suggested that the Perseid meteor shower lasts a long time. Although the weather and moon phases are unfavorable at the peak of August 12, you can watch them if you have the opportunity in the next few days. A week later, the moon phase will be very suitable. If you watch when the moon is bright, try to be in the shadow of the moonlight (allowing buildings and mountains to block the moon). Although you will lose a part of your vision, you can reduce the influence of moonlight.
While appreciating the meteor shower, how to capture the brilliant "blockbuster" of the meteor shower is also a matter of great concern to the public. In fact, shooting a meteor shower in the dark night is not as difficult as imagined. It only needs a SLR camera and a tripod.
When shooting, photographers can fix the camera on a tripod, aim at the sky area to be photographed, then set the focal length to infinity, adjust the camera’s wide-angle lens to long exposure, and finally adjust the camera’s aperture to around 17 , Sensitivity generally does not exceed 500. Everything is ready, just wait for the meteor to break into the lens.
On August 13, 2018, local time, Macedonia, a girl lying in a hammock on Mount Koziak, watching the Perseid meteor shower.
How does a meteor shower form? How can I find the Perseus?
For many people, making a wish to a meteor shower is a wonderful thing, but most people still have a little understanding of how a meteor shower is formed.
Liu Qian explained that most of the meteor showers originate from the debris left in the orbit of the comet (the Gemini meteor shower is an exception, the parent body is an asteroid rather than a comet). The comet orbits the sun in an oblate elliptical orbit. When it is close to the perihelion, it is slightly disintegrated due to heat. While advancing in the orbit, it leaves debris all the way in the orbit. If the comet's orbit intersects with the earth's orbit, a part of the debris will appear at the intersection. When the earth moves to this point, it will hit the meteoroid head-on, producing a meteor shower.
"The best viewing time for a meteor shower is determined by three factors: first, the maximum period of the meteor shower itself, that is, the moment when the meteoroids that break into the earth’s atmosphere are the densest; second, the height of the meteor shower’s radiant point rising in the sky , The closer to the zenith, the more suitable for viewing; third, due to the rotation of the earth, the number of meteors in the second half of the night is more than that of the first half of the night, and it is also more suitable for watching the meteor shower than in the first half of the night.” Liu Qian said, this year’s Perseid meteor shower’s maximum forecast Appearing from 21:00 to 24:00 on August 12, if the weather is clear, according to the stable performance of the Perseid meteor shower in previous years, there will be more than 100 meteors per hour.
When watching a meteor shower, people can also find Perseus by naked eyes. According to Cowen, Perseus is a beautiful constellation on the edge of the Milky Way in the northern sky. After dark, the Milky Way crosses the sky from south to north through the zenith, very dense between Altair and Vega, with Cygnus right in it.
If you patrol from Cygnus to the east of the Milky Way along the Milky Way, you will first find Cassiopeia, which is also located in the Milky Way. It is made up of 5 bright stars in the shape of the English letter "W", which is very striking. Continue down the Milky Way, and you will encounter a "human" shaped Perseus composed of several stars of magnitude 2 and 3.
On August 12, 2019 local time, Belarus, a Perseid meteor shower crossed the night sky on the ruins of a medieval castle in the village of Kriva, about 100 kilometers northwest of Minsk.
The romantic myth of the Perseid meteor shower
In fact, humans have been observing meteor showers for a long time. The ancients began to observe meteor showers as early as two thousand years ago. The earliest historical record of the Perseid meteor shower appeared in Chinese historical records in 36 AD. Japan and South Korea also recorded this meteor shower in detail in the 8th to 11th centuries.
The observation records of the Perseid meteor shower entrust mankind's beautiful hopes for unknown space. In the long history, romantic myths related to the Perseid meteor shower are circulating around the world.
The Perseid meteor shower is known as "Saint Laurent's Tears". In ancient Europe, August 10th is the festival of the Holy Spirit of Laurent. Since this festival is quite close to the occurrence of the annual Perseid meteor shower, the Perseid meteor shower is also known as the "Tears of Saint Laurent." ", adds a poignant color.
On August 12, 2018, a bolide illuminates the night sky by Lake Delinghakluk in Haixi Prefecture, Qinghai. Photo by Tang Zhengye
In ancient Greek mythology, Perseus is Perseus, the son of the god Zeus. With the assistance of Athena, the goddess of wisdom, and Hermes, the messenger of the gods, Perseus used the reflection of the bronze shield to chop off the head of Medusa the Gorgon. On the return journey, Perseus rescued Princess Andromeda from the sea monster. Later, Athena, the goddess of wisdom, lifted Perseus and Princess Andromeda into the sky, making them permanent companions for Perseus and Andromeda. Looking up at the starry sky now, the stars in Perseus happen to form the heroic image of Perseus holding Medusa's head in one hand and holding up a treasure knife in the other.
With the advancement of science and technology and the development of modern astronomy, the mysterious veil of the ancient Perseid meteor shower is being unveiled layer by layer. Now the public can also use the latest astronomical research results to rationally understand the Perseid meteor shower from a scientific perspective.
Tonight, the annual "horoscope" Perseid meteor shower will arrive as scheduled. Are you ready to make any wishes?