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Gemini Meteor

A Geminid meteor streaks through the constellation of Orion on the night of the peak of the Geminid Meteor Shower.

Although the meteor was recorded in Orion, its apparent point of origin, the radiant, was in the constellation of Gemini.

The Geminid meteors are small bits of debris, most the size of grains of sand, left behind by asteroid 3200 Phaethon in its orbit around the Sun. Almost all other meteor showers are caused by debris left behind by comets, so this makes the Geminid meteors a little different.

A comet is made of gas, ice and dust. When it nears the Sun in it's orbit, the heat from the Sun makes the ice sublimate, going directly from a solid to gas. A large cloud of this material forms around the comet, and this debris is left behind in the comet's orbit. If the Earth happens to pass through a cloud of this debris, we get a meteor shower when the tiny bits of rock burn up as they enter the Earth's atmosphere.

Phaethon is classified as an asteroid, but asteroids don't usually leave behind this kind of trail of debris. Phaethon, however, may be an extinct or dormant comet whose short 1.5-year period and perihelion inside Mercury's orbit may have burned off most of the body's volatile components.

Subtle green, yellow and red colors in the meteor are from gasses vaporizing from the meteor's passage through the Earth's upper atmosphere where it burned up.

When the small piece of rocky debris is in orbit around the Sun, it is called a meteoroid. As it burns up in the Earth's atmosphere, it is called a meteor. If part of it survives re-entry and lands on the ground, it is called a meteorite.

Exposure Data
  • Lens: Canon 18-55mm f/3.5-5.6 IS Kit zoom lens
  • Focal Length: 18mm
  • Focal Ratio: f/3.5
  • Mount: Takahashi EM200 Temma 2M German equatorial mount
  • Guiding: Autoguided concurrently with longer focal length shots
  • Camera: Unmodified Canon EOS 600D (T3i) DSLR
  • Exposure: 24 x 3 min for background, 1 x 3 min for meteor
  • ISO: 800
  • File Format: JPEG
  • White Balance: Custom for daylight
  • In-Camera Noise Reduction: Off
  • Filter: None
  • Date: December 13, 2012
  • Time: 11:50 p.m. EST
  • Location: Steelmantown, NJ
  • Calibration: None
  • Processing: Stacked in Images Plus, adjusted in Photoshop CS5

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