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Red flickering of star?

  1. Jan 14, 2012 #1
    so I was just looking up at the sky, as you do...
    and I noticed one star was flickering red, I believe it was betelgeuse - as far as i could see on my sky map app.
    Could any one tell me the reasoning for this flickering? as none of the other stars visible were doing this - at least as far as i could tell.

  2. jcsd
  3. Jan 14, 2012 #2
    How close was it to the horizon? If star light has to pass through lots of horizon before it gets to you the range of flickering will be much greater than a star above it.
  4. Jan 14, 2012 #3
    At least 45 Degrees above the horizon.
  5. Jan 14, 2012 #4
    Even at that height, this flickering would just be atmospheric effects.
  6. Jan 14, 2012 #5


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    Betelgeuse is pretty bright too. Flickering is much harder to discern with dimmer stars. You will see the flickering of the dimmer stars through a telescope.
  7. Jan 14, 2012 #6
    Although this makes sense i'm still a little confused. Stars that are closer to the horizon and stars that are near the star in question do not have this flickering?

    Edit:@chemisttree - ok that makes sense now, your reply was posted while typing mine. :)

  8. Jan 14, 2012 #7


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    Take a look at Sirius just after it becomes visible. It looks like police lights, going from red to blue to white and everything in between thanks to the atmosphere when it's low on the horizon.
  9. Jan 15, 2012 #8
    Funny, I was looking at Betelgeuse a few nights ago and wondered the exact same thing.
  10. Jan 15, 2012 #9
    Thanks for your replies everyone.
    I shall be sure to check Sirius out :)
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