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Distance to stars from my house using the parallax technique?

  1. May 30, 2009 #1
    Is it possible to find the distance to stars from my house using the parallax technique? If I can how close does a star have to be to be measured in a month instead of six months?
     
  2. jcsd
  3. May 30, 2009 #2

    Nabeshin

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    Re: Parallax

    If I didn't know any better I'd say you were trying to do this yourself.

    A star at a distance of 1 pc displays a parallax of 1 arcsecond. There are no stars closer than 1pc, so even the nearest are going to display a parallax siginificantly smaller than 1 arcsecond. And these are annual parallax numbers. If you want to try the measurements in only a month, you can expect much smaller parallaxes, on the order of 1/50 of an arcsecond for typical stars.

    So, unless you have that kind of resolving power, I'd say it's out of the question.
     
  4. May 30, 2009 #3
    Re: Parallax

    So would I be able to measure things that would require a longer amount of time?
     
  5. May 30, 2009 #4

    Nabeshin

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    Re: Parallax

    Probably not. Like I said annual parallaxes are going to be less than one arc second. Significantly less, but it's probably even optimistic to hope to get some in the neighborhood of 1/10 of an arcsecond. Annually. Also, given the fact that even under the best of seeing conditions the earth's atmosphere limits resolution to about .5 arcseconds, it seems a daunting task indeed.

    Getting down to .5 arcseconds isn't actually that hard, and only requires a ~8-10 inch diameter telescope. But taking precise enough measurements to detect the parallax, owing to the damned atmosphere, would be near impossible for an amateur (I think).
     
  6. May 30, 2009 #5

    Chronos

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    Re: Parallax

    You can do the math with simple trigonometry. The diameter of the earths orbit around the sun is approximately 186 million miles [a very convenient number - 1000 light seconds]. That forms the base of the parallax triangle you have to work with. One light year works out to around 6 trillion miles - a pretty large number compared to the diameter of earths orbit. You need a very accurate [and expensive] devise to reliably measure such small angles.
     
  7. May 30, 2009 #6

    DaveC426913

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    Re: Parallax

    OK, these answers are better than mine. Which was going to be 'Depends on how wide your house is'.
     
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