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    Re: sun sights
    From: Hewitt Schlereth
    Date: 2011 Jan 31, 14:45 -0400

    On 1/31/11, Patrick Goold  wrote:
    > Fred, Hewitt, Gary,
    > Thanks for your comments!  They are very helpful.  I am encouraged to think
    > that I am getting the hang of this but also chastened that I need to be more
    > careful.
    > I am embarrassed by the inexplicable subtraction error that Gary caught.
    > When corrected, the result is an intercept very near the one given by the
    > on-line calculator.
    > Treating the first sight as an upper limb instead of a lower brings that
    > value right into line with the others.  I can't imagine how I would have
    > made that mistake.  Given the combination of filters I use on the sextant
    > itself and on the artificial horizon, the image reflected by the AH and the
    > image reflected from the index mirror are different colors.  Orange over
    > green for a lower limb.  Could I really have inverted that without
    > noticing?  But there is no denying the observation looks much, much better
    > on the assumption that that is what happened.
    > Jeremy, I will try spreading out my shots.  I am using an artifical horizon,
    > though.   That limits how low one can observe.
    > Thank you all again for your help.
    > Best regards,
    > Patrick
    > On Mon, Jan 31, 2011 at 9:50 AM,  wrote:
    >>  I will look at your shots in my next exchange Patrick, but I will suggest
    >> spreading your shots out a bit more to give a better cut of the lines.   I
    >> would give at least 2 hours, and preferably three between observations so
    >> that there is larger change in azimuth.
    >> Jeremy

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