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Relative stargazing

  1. Jul 23, 2010 #1
    Does the time taken for a stars light to reach us, relative to it's true position as it moves through the galaxy give us a time distorted view of the night sky? I assume so, has there ever been an attempt to adjust this time distortion to give us a true representation of what we are really looking at?

    Would this potentially affect how we model objects in space, given that our photography gives us misrepresentations?
  2. jcsd
  3. Jul 23, 2010 #2


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    The difference would be pretty insignificant. The stars with the largest proper motions tend to be the closer stars and light takes less time to reach us from them. For example 61 Cygni has one of the highest proper motions, but is only 11.35 light years distant. With its proper motion, in 11.35 years it will have shift position by about 1 arc min, or approximately 1/30 the width of the Moon.

    The majority of the stars we see at night are very bright stars that are farther away. Consequently, they have small proper motions. Polaris, the north star is 430 light years away, but has a small proper motion. In the time it takes for its light to reach us, it will only have shifted 20 arc sec, or 1/90 of the width of the Moon.
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