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    Parallel rays of light from Stars?
    From: Mike Freeman
    Date: 2017 Jan 31, 23:23 -0800

    Curiosity tends to get the better of me.................

    When I read the rays of light from stars arrive at Earth parallel I thought a calculation was needed to confirm. I chose Sirius (8.611 lyr) as it is possibly the closest navigational star and will provide greater error.

    I soon discovered I did not have a calculator long enough so wondered who might have one. Now I can get a 3 metre length of skirting board into my Land Rover Defender 110. Clearly someone with an ordinary car would not be able to carry such a device around with them. I therefore posted on a Land Rover forum for a mathematical genius with a big calculator. 

    Soon managed to determine 1 minute of arc from Sirius at Earth distance is an amazing +/- 14,730,933,173.9 miles depending on which Pii used!

    To complete the calculation I found an online calculator and have managed to determine the maximum error we are ignoring by assuming the rays of light are in fact parallel is around 20 metres.

    The calculation I did was diameter of Earth orbit around Sun x 1760 divide by 14,730,933,173.9

    This calculation obviously does confirm we can ignore parallax but I am just wondering if someone with a calculator the length of a Land Rover can confirm is correct.



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