The Orionids are one of the most famous rains of stars of the year. These have the particularity that they can be seen from any point of the planet (its decline (+16º) nears the Celestial Equator allows it to be observed from all over the globe) and, of course, do not require special instruments to contemplate them: meteors can be seen with the naked eye.
This nocturnal spectacle comes from the particles of comet 1P / Halley – one of the most well-known comets – that visit our planet every 76 years (so we can see it again in 2062, still a few years away) and the name Orionidas must to that the meteors depart of Constellation of Orion.
How to locate this starting point of the meteors? Very easy. The constellation of Orion has in its center three stars aligned and almost of the same brightness, called ‘the three Marias’. But if what we want to see is a meteor of long distance, we will direct our sight to the radiant and then to 90 degrees of it, thus we will take advantage of the trajectory of the meteors in its entire splendor. We remember that all the shooting stars will have a direction opposite to the radiant one.
To see this rain of stars we recommend you do it between midnight and sunrise – no matter the country where you are – from a dark place and away from the light pollution (away from the big cities if possible) and contemplate them on a hammock or similar, lying face up.
The fact that the sky is clear of clouds will also be a determining factor. For the Moon we will not have to worry, since in the day of maximum activity of the meteor shower will be to 4%. This day is the night of October 21-22; in particular, the peak is scheduled for 20.00 UTC on October 21 and, as we have said, can be seen from both hemispheres of the planet.
It is a moderate star rain. About 20 meteors are expected per hour, with a speed of 66 km / s. The color of these meteors is generally green-yellow and often leaves behind a wake that persists for a few seconds, as they are formed by large particles that produce persistent strokes. It will not be like the Perseids or the Geminids (which are around 120 meteors per hour), but it is certainly a spectacle that every fan of astronomy would not want to miss. We know that it is not the strongest but the most beautiful of the year.
This year, the Moon blocked the Eta acuarids and the Perseids, but the Quadrantids, the Lirids, the Delta Aquarids, the Orionids, the Leonids (in November) and the Geminids (in December) do not present this visual obstacle.
Not to miss the event:
- When: October 4 to November 14, 2017
- The best night: October 21-22
- Maximum activity: October 21 at 20h UTC
- Moon phase: 4%
- Number and speed: +20 Meteors / hour / 66 Km / s
- Origin (radiant): Orion constellation
- Radiant Coordinates: Right Ascension 06h 20m, Declination + 15.5º
- Comet associated: 1P / Halley