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    Re: Off Center Sextant Scope Observations
    From: Greg R_
    Date: 2007 Nov 22, 18:22 -0800
    I haven't researched this in depth, but my instinct is would it really matter? Assuming you're talking about some sort of refraction error (through the sextant scope optics, not the atmosphere), since you're using the sextant's mirrors to make the lower limb tangent to the horizon wouldn't both be refracted by pretty much the same amount if viewed at that point (or really any point) of the scope?  
    But you can probably answer you own question - how close do your observations come to a known GPS position for the same location? If you can get to within a mile or so consistently from a shore location (no matter what part of the scope you use for the sight) I'd say not to worry about it.  :-)
    ----- Original Message -----
    From: "Greg Rudzinski" <gregrudzinski@yahoo.com>
    To: "NavList" <NavList@fer3.com>
    Sent: Thursday, November 22, 2007 4:39 PM
    Subject: [NavList 4015] Off Center Sextant Scope Observations

    > What happens to an image of a celestial body when viewed off center in
    > a sextant scope? I have a bad habit of using the lower half of the
    > field of view when taking lower limb observations of the sun. I
    > suspect that this increases the observed altitude slightly.
    > Greg Rudzinski

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