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The Perseid meteor shower , the most important one in the year, also known as the “San Lorenzo Tears” since they take place really close to the holiday for the Spanish martyr by the same name, will peak on August 12, according to the National Astronomical Observatory.
Although this celestial show began being visible in July, the peak of this stunning meteor shower is expected to take place on August 12. Hence, the best moment to watch the Perseid shower will be from August 11 through 13 at night. If you want to avoid the moon, it is best to watch it once the sky is dark and before the Earth’s natural satellite appears.
These meteors can surpass 50 km/s and their activity rate can reach 200 meteors per hour. Although its peak usually takes place from August 11 to 13, the Perseids can be seen from July 17 to August 24.
Its high rates, along with good atmospheric conditions for observing them during Summer, makes the Perseids the most popular shower meteor and the easiest to watch in the year.
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Unfortunately, 2020 will not be the best year to watch the Perseid meteor shower because the Moon phase will impede the view of the shower peak, reducing visible meteors from over 60 per hour down to 15 to 20 per hour. However, the Perseids are rich in bright meteors and fireballs, so it will still be worth watching them.
Why does it happen?
As they orbit around the Sun, comets leave gases, dust, and debris (rock materials) that remain in an orbit similar to the comet.
Thus, each comet forms a ring comprised of numerous comet fragments. When the Earth, in its movement around the Sun, meets one of these rings, some of the rock fragments (meteoroids) are trapped by our planet’s gravitational field and fall at high speed through the atmosphere causing a meteor shower .
The friction with atmospherical gases calcines and vaporizes the meteors that seem bright for a fraction of a second, forming what is popularly known as shooting stars. They are not stars but particles of incandescent dust.
The height at which a meteor becomes bright depends on the speed at which it penetrates the atmosphere, which is usually about 100 km. Nevertheless, the high brightness and traverse speed of some meteors cause a spectacular effect, giving the illusion to the observer that they are pretty close.
Meteoroids with a mass under 1 kg completely calcine in the atmosphere, but those with more density (of rocky or metal consistency) form meteorites: calcined remains that fall to the ground.
Each year, in early August, Earth crosses the orbit of the 109P/Swift-Tuttle comet, which has a 133 years long period and that last went near the Sun in 1992. This orbit is full of small particles, such as grains of sand or smaller, that have been previously released by the comet. When these particles, that used to be part of the comet’s tail, enter the Earth’s atmosphere, friction heats them until they are vaporized at great heights.
This meteor shower seems to have a single center of origin, a point from which all shooting stars seem to come from. This point is called “radiant” and its location is used to name the shower. Hence, the Perseids have their radiant on the constellation Perseus.
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How to observe the Perseids?
According to the National Astronomical Observatory, you can watch the shower from anywhere with a dark sky. Of course, it is best to watch it from a place with few obstacles for the sight, such as buildings, trees, or mountains, and not to use optical instruments that limit the field of vision.
Although the Perseids come from the constellation Perseus, they can be seen all over the sky, so it is best to look at the darkest areas, in the opposite direction of the Moon in case you watch them before the sunset. However, it is best to lie down and wait for your eyes to get used to the dark.
The number of meteors that can be seen per hour can vary a lot. You could watch a hundred of them per hour in a dark place with the radiant high in the horizon. Nevertheless, the number of meteors can change depending on the density of the fragments, that is why concrete predictions about the specific number of meteors based on the day and hour are difficult to achieve and usually have high uncertainty.
