The Orionid meteor shower is reaching its peak during the night of Wednesday (21st) and the early morning of Thursday (22nd), according to Olhar Digital. This event occurs annually between October 2nd and November 7th, although the peak can vary between October 21st and 23rd.
During this period, it is expected that between 10 and 20 meteors per hour will be visible. The phenomenon happens when the Earth passes through the debris trail left by Halley's Comet, which travels through the inner Solar System every 76 years. Upon entering the Earth's atmosphere, these particles ignite, generating the luminous trails known as meteors.
The name Orionids derives from the constellation Orion, as the trails appear to emanate from this celestial point, near the star Betelgeuse. Although the radiant is in the northern celestial hemisphere, the shower is easily observable in Brazil. The fragments reach the atmosphere at impressive speeds of 67 kilometers per second, which is equivalent to 241 thousand km/h.
Even with such high speed, the luminous traces usually last a few seconds, providing a visually worthy spectacle. Under certain circumstances, the meteors can intensify, turning into fireballs visible to the naked eye, surpassing the brightness of any star.
In addition to the Orionids, Halley's Comet is also responsible for the Eta Aquariids shower, which occurs annually in May.
Marcelo Zurita, president of the Paraíba Astronomy Association (APA), a member of the Brazilian Astronomical Society (SAB), technical director of the Brazilian Meteor Observation Network (BRAMON), and columnist for Olhar Digital, states that the official date for the Orionids peak is October 21st, reiterating that, in practice, there may be small variations from one year to another.
Zurita explains that the precision in determining the peak depends on the debris trail; older and established showers, like the Orionids, have more dispersed and less uniform trails, which prevents the peak date from always falling on the same day.
According to the astronomer, there are two main factors influencing the event. The first is that the peak can only be measured by calculating the number of meteors per hour, usually by radio detection, which ignores local weather conditions. Since the trail is not homogeneous, the highest rate may occur on different days. The second factor is the leap year; when there is an extra day in February, subsequent showers tend to occur one day earlier. For the Orionids, this could place the peak between the 20th and 23rd, depending on the study.
Another agent that can cause variations in peak dates are gravitational interactions with other planets, especially the gas giants, which modify the geometry of the debris trail. However, Zurita points out that this is not the case for this year's Orionids, suggesting that the divergence between sources is due to different studies.
Additionally, because the Earth year has 365 and a quarter days, there is a compensation of approximately six hours between one year and the next. For this reason, in astronomy, dates are not used as references for meteor shower calculations; the solar longitude parameter, which defines the Earth's position in its orbit regardless of the date, is preferred.
The historical solar longitude of the Orionids maximum for 2026 corresponds to 4 PM (Brasília time) on October 21st, projecting the peak for the early morning of the 22nd.
The specialist advises that the best approach is to monitor the shower over several days, without focusing on a single date. Zurita clarifies that between Tuesday (20th) and Friday (23rd), the hourly rate of meteors may not show a large variation, making it valuable to observe the Orionids on any of these days.
The Orionids shower is visible in both the Northern and Southern Hemispheres. According to the astronomical observation guide InTheSky.org, for those observing in São Paulo, the peak of activity begins around 10:50 PM on Wednesday (Brasília time) and remains visible until 5 AM on Thursday, before dawn.
The ideal time for observation is in the late morning hours, when the radiant is higher in the sky. In the São Paulo area, it can reach about 50° above the eastern horizon. At this time, it is estimated that up to 11 meteors per hour can be seen at the height of the shower. In locations with low light pollution and clear skies, the count can range between 15 and 20 per hour, while in large urban centers, pollution reduces the average to 5 to 10 meteors per hour.
To locate the meteors, one should look towards the east, in the direction of sunrise and the constellation Orion. Around 3 AM, the radiant will be at an altitude of 30°, rising to 50° near 5 AM. The longest and brightest meteors appear between 45° and 90° away from this point.
Sophisticated equipment, such as telescopes or binoculars, is not necessary. It is recommended to find a dark location, away from city lights, and allow your eyes to adapt to the darkness for about 20 minutes. Applications such as Stellarium, Star Walk, or SkySafari help in locating Orion. When spotting a shooting star, it is traditional to make a wish.
