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    Re: Are higher altitude sights inherently less accurate?
    From: Geoffrey Kolbe
    Date: 2012 May 02, 20:50 +0100

    When a star is near the horizon, there is no problem in knowing which
    direction to face to measure its altitude.
    But suppose you are measuring the altitude of a star on your zenith.
    The altitude will be 90 degrees. Which direction do you face to
    measure the altitude? When a star is on your zenith it doesn't
    matter, of course. You can face in any direction.
    But now suppose the star is a degree away from being on your zenith -
    how to you figure out which direction to face to measure its altitude
    then? You can see that without paying very careful attention to the
    direction you face (the azimuth) you could easily be out by a couple
    of degrees in the star's altitude!
     From this example, I hope you can understand that as the altitude of
    a celestial body increases, the greater the difficulty in determining
    the azimuth at which you should measure the altitude of the body.
    (Too, the error how vertical your sextant is becomes rapidly more
    important). And in consequence, errors in high altitude sights will increase.
    Geoffrey Kolbe
    At 15:23 02/05/2012, you wrote:
    >I have been loking at averages of my sights and higher altitudes
    >seem to have larger intercepts. Using an AH and reading Hs of over
    >100 degrees, Ha over 50. It seems to take longer to find high
    >altitude bodies in the mirror but is there something in the process
    >which introduces more risk of error?
    >NavList message boards and member settings: www.fer3.com/NavList
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