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    Re: True Distance vs. Observed Distance
    From: Bill B
    Date: 2012 Sep 17, 18:53 -0400

    On 9/17/2012 3:09 PM, Marcel Tschudin wrote:
    > Looking at Bill's Excel spread sheet "A Nav Ang Sep Refract Mas" shows
    > that he did indeed use this formula. I was however not able to calculate
    > with it the star distance of Greg's observation.
    Just finished tests with the .xlsx version posted. Spreadsheets attached.
    I don't think I have enough information to use with the spread sheet for
    both evenings.
    Using the location, elevation, temp and pressure from Greg's 9/15/12
    3:38 PM posting and the cel nav data from the "f2-Picsture-70.png" image
    attached to his 9/16/12 12:37 AM posting I obtain the following:
    Deneb/Vega   23d 50!4
    Alioth/Aikaid  10d 27!6
    The Deneb/Vega exactly matches Greg's earlier Tamaya observation, but
    since I do not know the time of the prior evenings observation, it is
    apples to oranges.
    When developing the spreadsheet in 2005, I added elevation and perhaps a
    few other things Alex did not feel were significant like calculating
    refraction from a star's Hc, rather than working backwards from the
    almanac tables (if I recall correctly).  When we compared notes were
    were usually spot on, and seldom more that 0!1 apart.  Given Alex's
    expertise (with the possible exception of abnormal refraction ;-), I
    tend to trust our numbers.
    Bill B

    File: 120640.deneb-vega-test.zip
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