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    Re: Bygrave Scale Lengths
    From: Hewitt Schlereth
    Date: 2013 Jan 30, 12:16 -0800

    Wolfgang, would it be possible to see a copy of the F-Tables, either complete 
    or in part? I'd be particularly interested to see the explanation of the 
    method. From the description in my 1977 Bowditch it looks like they are 
    similar to Dreisonstock.
    
    Danke sehr,
    
    Hewitt
    
    
    
    
    
    Sent from my iPad
    
    On Jan 30, 2013, at 11:49 AM, "Wolfgang Hasper"  wrote:
    
    > Brad,
    > 
    >> Bei d nahe 0 oder t nahe 0 und 90  verwende F-Tafel
    > 
    > translates to 
    > 
    > "With dec close to 0° or LHA close to 0° and 90° use 
    > F-Tables" 
    > 
    > (nomenclature adapted)
    > 
    > F-Tables being the alternative German sight reduction 
    > method in these days.
    > 
    > Best
    > Wolfgang
    > 
    > 
    > 
    > Am Mittwoch, 30. Januar 2013 15:21 schrieb Brad Morris:
    >> Hi Gary
    >> 
    >> Image 122161.img_2160.jpg tells the tale!
    >> 
    >> In it, we see the rules for using the device. 
    >> Within those rules, we see the standard
    >> admonishments for the MHR1, with one major and
    >> glaring change.  In German, we have:
    >> 
    >> Bei d nahe 0 oder t nahe 0 und 90  verwende F-Tafel
    >> 
    >> Which I loosely translate to:
    >> 
    >> Do not use the slide rule (F-Tafel) when declination
    >> is near zero deg or when the hour angle is near 0 or
    >> 90 deg.
    >> 
    >> The is no longer any numerical prohibition like 0
    >> deg 20 min or 89 deg 40 min.  It just says "near"
    >> (nahe).  This could be understood to say the same
    >> thing, since 20 min is near to zero.
    >> 
    >> But given the precise directions of the MHR1, I
    >> would like to think that near now means that the
    >> scale has been extended downwards and upwards, as we
    >> have discussed, towards 0 and 90 deg.  To what
    >> value?  The images do not reveal this data point. 
    >> Pity.  I'd like to think that it went to within an
    >> arc minute, the trick of a tiny offset to include 0
    >> deg 90 deg not withstanding.
    >> 
    >> What do you make of the conversion table, the
    >> adjustment knobs and the magnifying glass? 
    >> Magnifiers are typically associated with verniers
    >> and fine graduations.
    >> 
    >> Regards
    >> Brad
    >> 
    >> On Jan 30, 2013 12:39 AM, "Gary LaPook" 
    >  wrote:
    >>> ------------------------------
    >>> 
    >>> I am attaching some photos I took of the MHR2 in
    >>> London in 2009.
    >>> 
    >>> gl
    >>> 
    >>> +++++++++
    >>> 
    >>> I would be very curious to see what the scale
    >>> lengths and operating ranges of the MHR2 table top
    >>> calculator. Ronald - Do you know these values?
    >>> 
    >>> ++++++
    >>> --------------------------------------------------
    >>> -------------- NavList message boards and member
    >>> settings: www.fer3.com/NavList Members may
    >>> optionally receive posts by email. To cancel email
    >>> delivery, send a message to NoMail[at]fer3.com
    >>> --------------------------------------------------
    >>> --------------
    >>> 
    >>> Linked File:
    >>> http://www.fer3.com/arc/imgx/f1-IMG_2170.JPG
    >>> 
    >>> *Attached File:
    >>> 122161.img_2160.jpg>> .img_2160.jpg> *
    >>> *Attached File:
    >>> 122161.img_2161.jpg>> .img_2161.jpg> *
    >>> *Attached File:
    >>> 122161.img_2162.jpg>> .img_2162.jpg> *
    >>> *Attached File:
    >>> 122161.img_2164.jpg>> .img_2164.jpg> *
    >>> *Attached File:
    >>> 122161.img_2166.jpg>> .img_2166.jpg> *
    >>> *Attached File:
    >>> 122161.img_2167.jpg>> .img_2167.jpg> *
    >>> *Attached File:
    >>> 122161.img_2168.jpg>> .img_2168.jpg> *
    >>> *Attached File:
    >>> 122161.img_2169.jpg>> .img_2169.jpg> *
    >>> 
    >>> View and reply to this message:
    >>> http://fer3.com/arc/m2.aspx?i=122161
    >> 
    >> View and reply to this message:
    >> http://fer3.com/arc/m2.aspx?i=122166
    > 
    > 
    > 
    > 
    > View and reply to this message: http://fer3.com/arc/m2.aspx?i=122171
    > 
    > 
    
    
    
    

       
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