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From: Fred Hebard (no email)
Date: Sun May 14 2006 - 09:56:48 EDT

  • Next message: Red: "Re: sextant calibration"

    Roger,

    Welcome!

     From your lat-long, you're not in the U.S. If you were in the U.S.,
    there's a very nice series of topo maps at

    http://www.topozone.com/

    You would be able to place your elevation within 20 feet using
    those. There may be a similar resource available in your country
    (Australia?).

    If you could measure the angular distance between the islands you are
    viewing, knowing their true distance apart from the chart, you could
    compute your distance from the islands, that would be the hypotenuse
    of a right triangle. The distance you measure on your chart would be
    the base of the right triangle. Your elevation would be the height.
    The accuracy of this would depend on how accurately you measure the
    angular distance and the distances involved.

    I also don't know whether refraction would affect your angular
    distance. Perhaps one of the list gurus will chime in here on that.

    Fred

    On May 14, 2006, at 6:41 AM, Roger Puttman wrote:

    > Hi,
    >
    > I'm brand new to this site so thanks for having me!
    >
    > The first question I have is: I live on a hill overlooking the
    > ocean but dont know my elevation to set the dip. Given I know
    > where I am and can see some islands offshore is there a way I can
    > determine my altitude? I have a chart and can accurately place my
    > house and the islands so there must be a way....I just cant figure
    > it out. I can get off my bum and go down the beach and take sights
    > but it is kind of fun to be able to do it from the backyard...
    >
    > 32.46 S 115.75 E (decimal lat and long, my god what a dogs breakfast)
    >
    >
    >
    >> T


  • Next message: Red: "Re: sextant calibration"



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