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    Re: Modifications to 2102-D
    From: Brad Morris
    Date: 2009 Aug 13, 14:15 -0400

    Hi Gary
    Yes, that is an approximation that can and does work. Off list, Chief Franklin recommended just the
    same thing. I felt that there was enough error to not make me happy.
    What I wanted was to have the sextant preset to nearly the correct value.  Doing
    so eliminates (at least for me) the lack of certainty as to exactly which star is the right one and
    makes it easier to bring the star to the horizon.  I assume the midpoint of twilight for time and go
    from there.  The altitudes and azimuths are so close for the 15 minutes (or so at my latitude) as to
    not make a difference.
    To get the star in the view, yes, I use my Bygrave.  Why?  Because I can and it is fun!  Nothing like
    the feel of that instrument in practice.
    Best Regards
    -----Original Message-----
    From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of glapook@pacbell.net
    Sent: Thursday, August 13, 2009 1:12 PM
    To: NavList
    Subject: [NavList 9494] Re: Modifications to 2102-D
    Brad wrote:
    "I just use my to determine which stars would be practical.  Since my
    latitude is 40 north, it places me right between the N35 and the N45
    blue templates.  Therefore, the altitudes and azimuths given really
    don't do the trick. "
    "Once I have the list, I swap over to the Bygrave to calculate the
    altitude and azimuth of each.  That way, when I am ready to swing the
    arc, I can preset the sextant to the expected altitude and point via
    the compass. Generally, the star is right in the telescope! "
    A trick you can use to get better accuracy for latitudes between the
    template latitudes is to set LHA Aries (either using the almanac
    method or my modification or Chief Franklin's modification) and then
    take the template off the center pin and slide it north of south until
    the zenith is aligned with your DR latitude. This isn't perfect but
    will be accurate enough for you to be able to preset your sextant.
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