Thursday, October 28

When to see the Perseids and how to achieve optimal vision

The waning phase of the Moon will allow this year a optimal observation of the “perseids”, the rain of stars that occurs every summer, popularly known as “Tears of San Lorenzo” because its peak coincides with the days before and after that feast of the saints.

It will not be the Moon, but the clouds that make it difficult in some places to contemplate the rain of stars, since, after several days of completely clear skies In most of the country, storms and partially cloudy skies are going to be a constant in many communities during the coming days.

They are neither stars nor tears, but residual dust and rocks from a comet (the Swift-Tuttle) that collided with the Earth’s atmosphere they become “balls of fire” and at a speed of up to 50 kilometers per second they draw those luminous lines that unleash one of the most characteristic astronomical spectacles of summer nights in the northern hemisphere.

The National Astronomical Observatory (OAN) has recalled that the Perseids begin to be seen in the sky in mid-July and they last until the end of August, but the maximum activity is recorded each year between August 11 and 13, when that shower can reach up to 200 meteors per hour.

During the last nights the “tears” have already crossed the sky and generated fireballs especially bright that have already been recorded by the detectors that the Southeastern European Fireball and Meteor Network has in the La Hita Astronomical Complex (Toledo) and in nine other observatories located in different places in Andalusia.

But the true spectacle generated by the “Tears of San Lorenzo” will take place during the nights from 11 to 13 (between Tuesday and Thursday of this week) and the best time to observe it will be the first hours of the night, when the sky will be darkest, before the moon rises, although the satellite will not be a major obstacle this year because it is in a waning phase.

Why are they formed? Because all comets, in their orbits around the Sun, leave a trail of gases, cosmic dust and rocks that remain in an orbit very similar to that described by the parent comet, and when the Earth finds one of those rings, some of these fragments are trapped by the gravitational field and enter the atmosphere at high speed forming that “shower of stars”, according to the OAN.

Every summer the Earth crosses the orbit of Comet Swift-Tuttle, which is full of those small particles, like grains of sand and even smaller, that they had been released by the comet in its previous steps.

The Observatory data reveals that the brightness and speed of these meteors they cause a spectacular effect and the “illusion” that they are very close, although in reality the “Perseids” (so named because they “seem” to come from the constellation of Perseus) occur about 100 kilometers away.

The importance and popularity of this “meteor shower” draws the attention of the main astronomical societies and institutions every year, which organize activities to contemplate the show and live broadcasts, such as those programmed by the La Hita Astronomical Complex or the Instituto de Astrof√≠sica de Canarias with high quality cameras.

Because to see the “Perseids” you do not need telescopes or optical instruments – it is enough to look at the sky from dark places and as far as possible from sources of light pollution – but yes to observe how those meteors hit the Moon.

Lacking an atmosphere, these meteors collide directly with the lunar surface at speeds that can exceed 200,000 kilometers per hour, an impact that causes their sudden destruction and the formation of new craters; a collision invisible to the human eye, but not for telescopes.

A spectacle in the sky and an inexhaustible source of information for scientists, who each year focus on those tears and those collisions –some debris even impact the earth’s soil-.

The Astrophysical Institute of the Canary Islands and the Polytechnic University of Madrid have joined this year the citizen science project “Star Counters” financed by the Spanish Foundation for Science and Technology under the Ministry of Science and Innovation and have joined the didactic activities for anyone to participate in the star count.

The IAC, in collaboration with the astronomical dissemination channel sky-live-tv, will broadcast live the “meteor shower” of the August 12 (Wednesday to Thursday night) from the observatories of Teide in Tenerife and Roque de los Muchachos on the island of La Palma.

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