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    Re: Making an artificial horizon, and leveling thereof
    From: Alan S
    Date: 2011 Jan 25, 20:56 -0800


    In answer to your question, the usual, so far as I know, way. Zero the micrometer, I'm using an Astra 111B sextant. Then zero the index arm.

    Re the AH shots listed, I focoused the sextant scope on the roof lines of small buildings, private residences, within 1/4 mile of where I stood, beyond that proceeding as sextant instructions I've seen say, adjusting the micrometer till I got an "unbroken horizon line", that being the aforementioned roof line. Read the error off the micrometer, subtracting for "on the arc", adding for "off the arc".

    As I noted in a reply to George, index errors, when any presented themselves, were very much smaller looking at an actual sea horizon, while standing on the beach. The relatively large errors presented while doing the listed shots are perhaps due to "operator error", the operator being yours truly, but barring gross misreading of the micrometer, which I don't think happened, the listed IE's are what I got. Of course, as Murphy observed, "anything that can go wrong, will".
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