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Orionides, the “autumn shooting stars” arrive on October 20th: when and where to observe them

In the night between Sunday 20 and Wednesday 23 October of this year will arrive peak from the Orionidsone of the most intense meteor showers of the autumn period and the first of a certain importance after that of Perseidsthe “stars of San Lorenzo” visible in August. The swarm actually occurs from late September to late November, but the next ones will be ideal days to see the “falling stars” as theactivity will be maximumalso reaching the 20-30 meteors per hour.

What are the Orionids and what is their origin

Whenever we talk about “shooting stars”, the correct term is actually meteors. It’s about small fragmentsof dimensions generally comparable to those of a grain of ricewhich are stationed in Earth’s orbit and which are periodically intercepted by our planet. Captured by Earth’s gravity, this natural debris passes through our atmosphere very high speed (about 60 km/s); friction with the air does the rest, igniting the fragments which then leave their characteristics in our skies light trails.

Meteor showers are produced by the disintegration of minor bodies in the Solar System, typically comets. The Orionids are no exception: they are in fact fragments of the famous one Halley’s comet (for astronomers 1P/Halley), a comet that returns to the inner Solar System every 76 years old approximately (last time in 1986).

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Halley’s comet photographed in 1986 during its last close pass with the Earth. Credits: NASA/W. Liller, Public domain, from Wikimedia Commons.

It’s a comet of great cultural interest since according to some it would be the Comet of the Nativity of which the Gospels tell. It was probably also the comet painted by Giotto in the Scrovegni Chapel in Padua, which the Tuscan painter may have seen with his own eyes during the passage of the comet 1301.

comet scrovegni chapel padua giotto
The comet depicted in Giotto’s Scrovegni Chapel in Padua.

The swarm gets this name from the fact that its radiant (i.e. the point from which the various light trails appear to start) is located in the constellation of Orion. The Orionids are among the fastest meteor showers, with meteors that can reach even 66 km/s (Almost 240,000 km/h!).

When and where to see the Orionids

The peak of the shower, that is, the moment of maximum frequency of the meteors, is during the night between 20 and 23 October. The best time to observe the Orionids is between midnight and dawnwhen the constellation Orion (in which the shower radiant is located) is highest in the sky in east direction.

All you need to do is point your gaze (thenaked eye will be fine) to the east and look for the unmistakable shapes of the constellation of Orion: a good part of the meteors will appear in that area of ​​the sky. But don’t worry: the meteors will still be visible in other parts of the sky, so even if you don’t look directly at Orion you can still find plenty of them, especially in areas with a particularly dark sky.

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Schematic representation of the constellation Orion.