The Orionid meteor shower takes place every October, and the peak of the display comes on October 20 and 21 this year. On Tuesday and Wednesday this week, observers could see up to 20 shooting stars per hour.
Annual meteor showers are usually the result of the Earth passing into the debris field left behind by a passing comet. The Orionid display is one of two such regular displays resulting from the passing of Comet Halley every 76 years (the other being the Eta Aquarid display each May).
Hunting for the bunter
At nighttime or in the pre-dawn sky, the Orionid meteor shower provides amateur skygazers a chance to see a beautiful display of shooting stars.
Not surprisingly, the Orionid meteor shower is centered on the constellation Orion. This is one of the easiest of all constellations to find in the night sky. Simply look for three bright stars huddled fairly close together in a near-perfect line. That is the belt of Orion.
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Starting around 11 pm, the display will first be seen rising over the eastern horizon. Observers wishing to see the celestial show at this time should look for a location with a clear, low view to the east. By 1am, the shower will be centered in the southeast, and will be higher in the sky (35 degrees above the horizon, as seen from Tucson, Arizona).
This display features fast-moving meteors, ripping through the atmosphere of Earth at velocities around 66 km/sec (almost 150,000 MPH). So, shooting stars from this display tend to be short-lived.
By 5 am, the display will be seen nearly due south, as the display reaches its maximum height in the sky (around 73 for locations around 30 degrees latitude). An hour later, the Orionids will be about five degrees below their peak latitude toward the southwest. At this time, sunlight will begin to interfere with observations, with sunrise due at around 6:30 in Tucson.
Two other, smaller, displays of shooting stars are also happening at the same time. The Episilon Geminids (seen just below an to the north, or left, of the main display) will contribute the occasional meteor to the night’s display, as will the Delta Aurigids, lightly to the north (left) of the Orionids.