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Post Info TOPIC: Orionid meteor shower


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Orionid meteor shower

Under cloudless skies,  the  Orionid meteor shower may make a fine display peaking on October 21 to 22.
The annual meteor shower occurs when Earth passes through the debris stream of Comet Halley, and meteoroids hit the atmosphere at  66 km/s (about 148,000 mph).
The shower is the second of two  meteor showers that occur each year as a result of Earth passing through the dust stream; the first is the Eta Aquarids.
The Orionid shower starts on the 17th of the month but will peak around the night of October 21 and will continue until the 27th.

"Under favourable conditions, about 20-25 Orionid meteors will burn in the sky" - Elenita Ingalia, officer in charge of Astronomical Research and Development Section at the Philippine Atmospheric Geophysical and Astronomical Services Administration (Pagasa).

Meteors are small fragments of cosmic debris entering Earth's atmosphere at extremely high speed. They vaporise due to friction with the air, leaving a streak of light that very quickly disappears.
It is thought  that Halley's comet sheds a blanket  6 meters thick of dust and ice on each pass.
Most of the small fragments of comet debris are smaller than a grain of sand, so almost all fragments disintegrate and never hit the earth's surface.
For observers around 40 degrees north latitude, the radiants rise high in the eastern sky (at least 45 degrees up) by about 2 a.m.
To find the Orionids, go outside and face South-southeast towards the constellation Orion. The radiant lies NE of Betelguese, near to the  border of  Gemini.
Visible nationwide, the Orionids are faint and swift. They are best seen  just with the naked eye.
The average brightness is around the magnitude 2 to 3;  the same as the stars in the Plough.
But fireballs can be expected around the  maximum. The expected ZHR (Zenith Hourly Rate) is estimated at 25 meteors per hour.
The meteors  don't have any colour/ white, and sometimes leave a glowing green ion train in their wake.

"Stay away from city lights though, because bright lights can spoil the visibility of meteors" - Elenita Ingalia.

Aside from city lights, thick clouds can ruin the event. An evening gibbous moon should not hamper too much the shower this year.)

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