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How do I calculate my location based only on the time of day/sunrise/sunset?

Discussion in 'Archived Threads 2001-2004' started by Don Black, Sep 5, 2001.

  1. 1 Sep 5, 2001
    Don Black

    Don Black Screenwriter

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    This is kind of a brain teaser for all of you space buffs. It has something to do with the position of the sun and the time of day at two different places. That somehow allows you to determine your longitude and lattitude. Any ideas guys? =)
     
  2. 2 Sep 6, 2001
    Kolya

    Kolya Stunt Coordinator

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    You use a sextant , of course.
     
  3. 3 Sep 6, 2001
    Jay H

    Jay H Producer

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  4. 4 Sep 6, 2001
    Julie K

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    GPS unit.
    Well, that's the best [​IMG]
    A sextant can be used, and what was traditionally used at sea, but on land a regular surveyor's theodolite can be used. Finding your location on land is easier too since you don't have to take the ship's motion into account. It's been a long time since I did this, so I'll just refer you to Textbook on Spherical Astronomy by W.M. Smart (Hey, if I had to wade through that old textbook with antiquated calculation methods, then you should too.)
    But basically, you measure the altitude of the sun or a star at two different times (or three on land for a very accurate fix). You will need an accurate time signal and knowledge of the sun's ephemeris if you use that. (You will also need to know the angular diameter of the sun at the time you make the measurements). If on a ship you need to have an approximate idea of where you are and the direction and speed you're traveling.
    Really, GPS is much better.
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    [Edited last by Julie K on September 06, 2001 at 10:46 AM]
     
  5. 5 Sep 6, 2001
    Glenn Overholt

    Glenn Overholt Producer

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    You're not saying that you're supposed to look at the sun through a surveyor's instrument and go blind, are you? Just curious.
    Glenn
     
  6. 6 Sep 6, 2001
    BrianW

    BrianW Cinematographer

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  7. 7 Sep 6, 2001
    Julie K

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    If you have a mylar filter, designed especially for solar observations, over the front of the theodolite, then yes, you can look directly at the sun through it. If you don't have one, then you can rig something up to project the image onto a metal plate.
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  8. 8 Sep 6, 2001
    Jay H

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  9. 9 Sep 6, 2001
    BrianW

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  10. 10 Sep 6, 2001
    Jay H

    Jay H Producer

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    Well BrianW, the sun method via sight only works twice, apparently, you have one more attempt. The next method of determining your lat/long and part 2 of Don's question is calculating your lat/long using only a strand of cooked (al dente) spaghetti and your nose.
    [​IMG]
    Jay
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  11. 11 Sep 8, 2001
    Don Black

    Don Black Screenwriter

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    Hmmm .. thanks guys. Does anyone else have some useful URL links? Thanks again.
     

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