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    Re: Dip Anomaly
    From: Ken Gebhart
    Date: 2008 Mar 13, 21:57 -0500

    I would think so.  First, I assume you are on land with the sextant
    propped up, and not hand held. Next, the horizon should be sighted
    with the top of the bubble, then the bottom of the bubble, and the
    readings averaged, and finally the sextant must be calibrated for
    accuracy.  The latter can be done with a star in the same manner.  My
    experience with bubble sextants is that repeatable readings can be
    obtained within 20 to 30 seconds of arc.
    Ken Gebhart
    On Mar 13, 2008, at 3:22 PM, Greg Rudzinski wrote:
    > Question for NAVLIST: Can a bubble sextant be used to measure dip
    > anomalies from a known height of eye? This would be a negative
    > measurement in minutes from bubble to horizon.
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