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    Re: UL vs LL: which is which when an artificial horizon is involved?
    From: Brad Morris
    Date: 2019 May 14, 13:49 -0400
    Tony

    You wrote:

    I need a way to understand and remember a rule of limb determination.


    May I suggest you play with your sextant and observe some building you can see with the naked eye.  Remove the telescope and sight tube.  The telescope merely inverts both paths, or not, depending on the type of telescope.

    Block the horizon path and observe the building with the sextant via the index path.  Write down what you see.  You are concerned with left right orientation as well as top bottom orientation.  Are they the same as the mark one eyeball, or different.

    Block the index mirror path and repeat the experiment.  Write down the orientations, same as before.

    Lay a simple mirror on the ground and observe the building using the horizon path.  This will simplify the Artificial Horizon experience, but no harm if you use the actual AH.  The AH really just provides a reflection but the image will be brighter in the mirror.  Write down the orientations, same as the other two times.

    I could just as easily tell you what you will see, but the easiest way for you to learn and commit what you learn to memory is to do this yourself.  You should end up with three paths (index mirror path, direct horizon path and reflected horizon path) and two orientations for each (left right and top bottom).  

    You could just draw the same three paths and puzzle it out mentally, but using the sextant to do it will help you to better commit the result to memory.

    If at the end of the experiment, you are still unsure, or wish to confirm your result, post your results!  The simple act of publication will lead you to clarity of purpose and stellar (heh, nice pun) observations.

    Brad
       
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