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    Re: Home made artificial horizon
    From: Robert Eno
    Date: 2011 Oct 5, 23:17 -0400

    I believe that Roald Amundsen also used a glass artificial horizon on his 
    journey to the South Pole in 1911-12.
    
    Robert
    ----- Original Message ----- 
    From: "Wolfgang Hasper" 
    To: 
    Sent: Wednesday, October 05, 2011 3:28 PM
    Subject: [NavList] Re: Home made artificial horizon
    
    
    Gary,
    mind that mercury will freeze at -38�C and you will
    likely encounter lower temperatures on your way to the
    pole. A strong argument for mirror type horizons.
    ;o)
    
    http://en.wikipedia.org/wiki/File:Pole-observation.jpg
    Nansen carried one on his sledge attempt for the pole,
    too.
    
    Wolfgang
    
    
    Am Mittwoch, 5. Oktober 2011 00:38 schrieb Gary LaPook:
    > But many real navigators on sledges and elsewhere
    > did carry liquid (including mercury) AHs.
    >
    > gl
    >
    > --- On Tue, 10/4/11, Geoffrey Kolbe
    >  wrote:
    >
    > From: Geoffrey Kolbe 
    > Subject: [NavList] Re: Home made artificial horizon
    > To: NavList@fer3.com
    > Date: Tuesday, October 4, 2011, 10:37 AM
    >
    >
    >
    > Robert wrote:
    >
    >
    > I can't take it
    > anymore!
    >
    >
    >
    > Seems like you folks are going to a great deal of
    > hassle and looking in every hidden corner for the
    > perfect levelling mechanism and/or to make an
    > effective artificial horizon. Short of using a pan
    > of motor oil or getting hold of some mercury, the
    > best option is, in my opinion, to just go out and
    > purchase a Freiberger artificial horizon which comes
    > with all you need to obtain pinpoint accuracy (as
    > much as is possible with a sextant).
    >
    >
    > No no, you don't understand Robert. There is a
    > satisfaction in the process of spending a great deal
    > of time and effort to build an AH as cheaply as
    > possible using plastic, string and sealing wax. ;-)
    >
    >
    > But on the matter of practicality, I have no doubt
    > that you are correct. Could you take the plastic
    > string and sealing wax AH to navigate your sledge to
    > the middle of the Antarctic? Or your camel to the
    > middle of the Sahara desert? Possibly, but people
    > have certainly been there and done that with a
    > Freiberger AH. I took the short cut many years ago
    > and bought one.
    >
    >
    > One note on the use of levels. Just because the
    > graduation on the level is only one mil say, (about
    > 3 MOA), does not mean that you are limited to an
    > accuracy of 1 mil in level adjustment. By turning
    > the level end for end for comparison and estimating
    > the bubble position to one tenth of a graduation, it
    > is possible to get an accuracy in level-ness at
    > least an order of magnitude better than the level
    > graduations would suggest.
    >
    >
    > Geoffrey Kolbe
    
    
    
    
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