Comet Encke

This is the year of the comet, so far, we’ve had Lemmon and Pan STARRS. Soon you’ll be able to see ISON, but for now you’ll have to settle for our “old faithful” comet Encke. It’s “old faithful” because it has the shortest orbit of any known periodic comet and appears every 3.3 years. Periodic means that it orbits the Sun in a reliable pattern like a planet.

Encke has an oval orbit, where it circles the Sun from inside Mercury’s orbit then loops out close to Jupiter before returning. It reaches its closest proximity to Earth every 33 years, when it’s most visible to us. The last time was 1997, and the next time will be 2030. This year will be its 62nd observed return.

It was first recorded as being seen in 1786, but not recognized as a returning comet until 1819 by German astronomer Johann Encke, hence its name. Comet Encke is believed to be the originator of the Taurid meteors. The Taurids have been observed for a few thousand years, so Encke most likely has been orbiting for at least that long. That fireball seen over Southern California last week probably came from the Taurid meteors.

Although it’s one of the brightest comets in the sky, Encke has been getting fainter with each passing orbit. That’s most likely due to it shedding material, leaving a pebbly trail of debris which we see as meteors. Currently, it’s about 3 miles in diameter.

Nov. 21 is its perihelion when it circles around the Sun and its tail becomes more visible. This is a predawn morning comet, so you’ll have to get up early to see it. It’s been visible with telescopes since September, and currently requires binoculars. Encke will brighten at the end of this month, but dawn’s light may interfere as Encke becomes visible slightly later each morning.

So, grab your binoculars and look in the eastern sky about 20 degrees above the horizon, slightly less than ¼ of the way up. You’ll need to do this about 2 hours before sunrise, or about 4:45 a.m. Look for a hazy star with a tail.

I’ve been doing this column for 13 years. Now that I’m 76, I’ve decided that this year will be my last year. If any of you want to take it over, just call Valley Publishing to tell them you want to take it over from me.


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