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    HO 211 (Ageton) Sadler method
    From: Paul Hirose
    Date: 2017 Sep 11, 14:33 -0700

    On 2017-09-11 8:03, Greg Rudzinski wrote:
     > The Ageton Classic is not a derivitive of the the Ageton Pub 211
    short table so is not subject to the errors you mention.
    Is Ageton Classic free of any danger zone, such as the inaccuracy near t
    = 90 in HO 211?
     > From: *Jing CDate: *2017 Sep 10, 22:51 -0700
     > I was reading through the archives and it seems that in the
    Ageton-Bayless method, the Sadler technique is required when a term
    called K is between 82 and 98 degrees otherwise Hc could be up to 30' off.
    In June and July 2016 I wrote on the accuracy of Ageton / HO 211 and the
    Sadler method. (The latter is not fully described in the Bayless book. A
    third rule is necessary to get the correct Z in all cases.)
    My tests showed the Sadler method is beneficial only in a small
    percentage of sights: "So rapid is the degradation of Sadler accuracy
    away from K=90, that you get best overall accuracy by limiting it to
    plus or minus three degrees from 90. In that case the RMS altitude error
    is .38', 88% of reductions are within 0.5', and the worst result in one
    million random problems is 8.5'."
    There are many more than just those two. Look for messages in June and
    July 2016 with "Ageton" or "Sadler" in the subject.

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