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    Re: Sight Reduction Tables for Small Boat Navigation byHewittSchlereth
    From: Gary LaPook
    Date: 2014 Jan 4, 23:06 -0800
    We have been discussing this all the way back to 2004.

    http://fer3.com/arc/m2.aspx/Bygrave-position-line-slide-rule-ZviDoron-feb-2004-w14450



    http://fer3.com/arc/m2.aspx/Bygrave-slide-rule-LaPook-sep-2008-g6329


    http://fer3.com/arc/m2.aspx/Bygrave-MHR1-locking-mechanism-construction-LaPook-sep-2009-g9993
    http://fer3.com/arc/m2.aspx/Bygrave-MHR1-locking-mechanism-construction-LaPook-oct-2009-g10029
    http://fer3.com/arc/m2.aspx/Bygrave-MHR1-locking-mechanism-construction-LaPook-oct-2009-g10043
    http://fer3.com/arc/m2.aspx/Bygraves-LaPook-jul-2009-g9116


    http://fer3.com/arc/m2.aspx/Bygrave-slide-rule-LaPook-sep-2008-g6329

    http://fer3.com/arc/m2.aspx/Accuracy-Bygrave-LaPook-jul-2009-g8973

    http://fer3.com/arc/m2.aspx/Cylindrical-Slide-Rules-LaPook-feb-2009-g7322

    Complete description of the flat version of the Bygrave

    https://sites.google.com/site/fredienoonan/other-flight-navigation-information/modern-bygrave-slide-rule

    An easy way to find what we have posted about the Bygrave over the years is to go to the archive and click on "all" for each year starting with 2004 then sort by subject. Scroll down looking for Bygrave realated posts.

    gl







    From: Nial McInerney <nialmac---.com>
    To: garylapook---.net
    Sent: Saturday, January 4, 2014 1:22 PM
    Subject: [NavList] Re: Sight Reduction Tables for Small Boat Navigation byHewittSchlereth


    I would absolutely love to have a Bygrave or a MHRI but where can I get the instructions to make one? The thing is I have a lathe in the basement and am an experienced machinist so should be able to produce a good one if I knew how.
    Nial
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    bygrave posts


    Bygrave position line slide rule
    From: zvidoron---COM
    Date: 28 Feb 2004 16:01
    Previous messageNext messageReply to this message
    Hello,
    Henry Hughes & Son of London, England used to make a cylindrical 3 part
    position line slide rule for astro navigationsometims called "Bygrave" that
    worked on the principal of solving two right angle triangels instea of the
    complete PZX in one calculation. Francis Chichester used one on his epic
    solo flight across the Tasman Sea (1931) and Weems in his book "Air
    Navigation - British Empire Edition" gives a drawing and a few details. I
    could not find any reference to it on the web.
    Has anyone - ever used one? got one? seen one? knows if they can be had and
    for how much? Any information will be gratefuly received.
    Thanks
    Zvi


    Re: Bygrave position line slide rule
    From: danallen46---NET
    Date: 28 Feb 2004 20:48
    Previous messageNext messageReply to this message
    Zvi Doron wrote on Saturday, February 28, 2004 8:02 AM:

    Henry Hughes & Son of London, England used to make a cylindrical 3 part
    position line slide rule for astro navigationsometims called "Bygrave" that
    worked on the principal of solving two right angle triangels instea of the
    complete PZX in one calculation. Francis Chichester used one on his epic
    solo flight across the Tasman Sea (1931) and Weems in his book "Air
    Navigation - British Empire Edition" gives a drawing and a few details. I
    could not find any reference to it on the web.
    Has anyone - ever used one? got one? seen one? knows if they can be had and
    for how much? Any information will be gratefuly received.

    ---

    I found one thing from Google:

    http://home.ecn.ab.ca/~jsavard/other/sr03.htm

    The Otis King Slide Rule

    This slide rule consists of a body with a helical scale, on which a sleeve
    with a similar helical scale could both slide and rotate. An outer sleeve
    then slid and rotated on that sleeve at one end, and at the other end was
    constricted to slide directly on the body. Marks at the two ends of that
    sleeve constituted the cursor of the slide rule; thus, instead of placing
    the two helical scales in coincidence, points on the two scales separated by
    the distance between the two cursor marks were treated as corresponding.

    The Otis King cylindrical slide rule was perhaps the most popular and
    inexpensive circular slide rule made.

    A special-purpose cylindrical slide rule made for use in sight reduction for
    celestial navigation, the Bygrave position-line slide rule, was based on the
    same principle.

    ---

    As a mathematician, I simply turned your problem into a different one: what
    the heck is an Otis King slide rule? Sounds very interesting!

    Dan
    Re: Bygrave position line slide rule
    From: zvidoron---COM
    Date: 29 Feb 2004 09:00
    Previous messageNext messageReply to this message

    Hi Dan Thanks for that - the Otis King is British made to the best of my knowldge. It has chrome scales and a black handle, two models were make, the K and the L, with different scale sets. They appear from time to time on eBay UK, the better deals have the instructtions and the box. They can fetch somewhere between 30-100 GBP. Excellent scans of one of these can be seen on the website of Mr. Atsushi Tomozawa of Japan. http://www5b.biglobe.ne.jp/~tomozawa/sr-annex/cat/other/otis-king/otis-kinge .htm You can also download instructions from the following website to understand how to operate one. http://sliderule.ozmanor.com/man/man-download.html The Bygrave has a roughly similar mechanical construction ()according to the one drawing I have) but the scales are dedicated to a two step process of solving the PZX triangle. Kind regards Zvi

    AW: Bygrave position line slide rule
    From: koeberer---DE
    Date: 1 Mar 2004 20:28
    Previous messageNext messageReply to this message
    Dear Mr. Doron,

    the Bygrave Slide Rule, a cylindrical slide rule like the Fuller or the Otis
    King, was invented in the 1920s to solve the navigational triangle in
    position line navigation. The ?Admiralty Navigation Manual?, Vol. III
    (London 1938) describes it on p. 128:

    ?The Bygrave Slide Rule consists of three concentric tubes, the innermost
    carrying a scale of logarithmic tangents and the one next to it a scale of
    logarithmic cosines, both scales being arranged in spiral form. This
    construction is made possible by dropping a perpendicular from X on the side
    PZ of the spherical triangle, as in the Ageton method, and solving the two
    right-angled triangles thus formed.?

    Another description can be found in the 1977 edition of the ?American
    Practical Navigator?, Vol. I, p. 604, in the historically interesting
    chapter on ?Comparison of various methods of Sight Reduction.There is also a
    picture of this slide rule on this page.

    A similar gadget called ?Höhenrechenschieber MHR1? was produced by Dennert &
    Pape in Germany before and during WWII. Although they must have been
    produced in sizable numbers most appear to have been lost during the war
    and/or thrown away as outdated later on; so they seem to be quite scarce
    these days: One ?MHR 1? reportedly was sold on e-bay for $ 1080 a couple of
    years ago. The ?Deutsches Museum? shows a couple of ?Höhenrechenschieber? in
    their new department on ?Computing? (shelf mark 78/255). I could also send
    you a picture of my ?MHR1? off-list, if you like.

    W. Köberer

    Re: Bygrave position line slide rule
    From: zvidoron---COM
    Date: 18 Mar 2004 22:14
    Previous messageNext messageReply to this message

    Hello, Based on the information and images Mr. Koberer kindly sent me and on some details and a drawing from Weems' book Air Navigation I have now built a fully working model of the Bygrave position line slide rule. It is 2-3 times larger than the original and is quite accurate, giving calculated positions to within about 1' of arc (1 nautical mile) with the inputs being Dec, Lat and LHA, so in effect it replaces the normal sight reduction tables. It took some 8 hours of work to make. Do contact me if you are interested in details. Kind regards Zvi

    Bygrave slide rule
    From: wnmpiccer---NL
    Date: 11 Dec 2005 14:00
    Previous messageNext messageReply to this message
    Is it possible to put a drawing/picture of this slide rule on the forum?
     
    I have been looking on the web but cannot find anything
     
    Thanks
     
    Willem Piccer

    Re: Bygrave slide rule
    From: zvidoron---COM
    Date: 11 Dec 2005 13:44
    Previous messageNext messageReply to this message
    I have collected some .PDF files and phographs regarding both the original Bygrave slide rule and its German copy MHR1 (some came from other members of this forum). However, I don't know how they can be posted on the web for all to see - maybe the mediator of the forum has a aord of advice?
     
    I have been toying with the idea of posting a webpage of my own covering the Bygrave and other items of interest to navigators and slide rule collectors but again don't know were to start.
     

    Re: Bygrave slide rule
    From: zvidoron---COM
    Date: 11 Dec 2005 13:44
    Previous messageNext messageReply to this message
    I have collected some .PDF files and phographs regarding both the original Bygrave slide rule and its German copy MHR1 (some came from other members of this forum). However, I don't know how they can be posted on the web for all to see - maybe the mediator of the forum has a aord of advice?
     
    I have been toying with the idea of posting a webpage of my own covering the Bygrave and other items of interest to navigators and slide rule collectors but again don't know were to start.
     












    bygrave posts


    Bygrave position line slide rule
    From: zvidoron---COM
    Date: 28 Feb 2004 16:01
    Previous messageNext messageReply to this message
    Hello,
    Henry Hughes & Son of London, England used to make a cylindrical 3 part
    position line slide rule for astro navigationsometims called "Bygrave" that
    worked on the principal of solving two right angle triangels instea of the
    complete PZX in one calculation. Francis Chichester used one on his epic
    solo flight across the Tasman Sea (1931) and Weems in his book "Air
    Navigation - British Empire Edition" gives a drawing and a few details. I
    could not find any reference to it on the web.
    Has anyone - ever used one? got one? seen one? knows if they can be had and
    for how much? Any information will be gratefuly received.
    Thanks
    Zvi


    Re: Bygrave position line slide rule
    From: danallen46---NET
    Date: 28 Feb 2004 20:48
    Previous messageNext messageReply to this message
    Zvi Doron wrote on Saturday, February 28, 2004 8:02 AM:

    Henry Hughes & Son of London, England used to make a cylindrical 3 part
    position line slide rule for astro navigationsometims called "Bygrave" that
    worked on the principal of solving two right angle triangels instea of the
    complete PZX in one calculation. Francis Chichester used one on his epic
    solo flight across the Tasman Sea (1931) and Weems in his book "Air
    Navigation - British Empire Edition" gives a drawing and a few details. I
    could not find any reference to it on the web.
    Has anyone - ever used one? got one? seen one? knows if they can be had and
    for how much? Any information will be gratefuly received.

    ---

    I found one thing from Google:

    http://home.ecn.ab.ca/~jsavard/other/sr03.htm

    The Otis King Slide Rule

    This slide rule consists of a body with a helical scale, on which a sleeve
    with a similar helical scale could both slide and rotate. An outer sleeve
    then slid and rotated on that sleeve at one end, and at the other end was
    constricted to slide directly on the body. Marks at the two ends of that
    sleeve constituted the cursor of the slide rule; thus, instead of placing
    the two helical scales in coincidence, points on the two scales separated by
    the distance between the two cursor marks were treated as corresponding.

    The Otis King cylindrical slide rule was perhaps the most popular and
    inexpensive circular slide rule made.

    A special-purpose cylindrical slide rule made for use in sight reduction for
    celestial navigation, the Bygrave position-line slide rule, was based on the
    same principle.

    ---

    As a mathematician, I simply turned your problem into a different one: what
    the heck is an Otis King slide rule? Sounds very interesting!

    Dan
    Re: Bygrave position line slide rule
    From: zvidoron---COM
    Date: 29 Feb 2004 09:00
    Previous messageNext messageReply to this message

    Hi Dan Thanks for that - the Otis King is British made to the best of my knowldge. It has chrome scales and a black handle, two models were make, the K and the L, with different scale sets. They appear from time to time on eBay UK, the better deals have the instructtions and the box. They can fetch somewhere between 30-100 GBP. Excellent scans of one of these can be seen on the website of Mr. Atsushi Tomozawa of Japan. http://www5b.biglobe.ne.jp/~tomozawa/sr-annex/cat/other/otis-king/otis-kinge .htm You can also download instructions from the following website to understand how to operate one. http://sliderule.ozmanor.com/man/man-download.html The Bygrave has a roughly similar mechanical construction ()according to the one drawing I have) but the scales are dedicated to a two step process of solving the PZX triangle. Kind regards Zvi

    AW: Bygrave position line slide rule
    From: koeberer---DE
    Date: 1 Mar 2004 20:28
    Previous messageNext messageReply to this message
    Dear Mr. Doron,

    the Bygrave Slide Rule, a cylindrical slide rule like the Fuller or the Otis
    King, was invented in the 1920s to solve the navigational triangle in
    position line navigation. The ?Admiralty Navigation Manual?, Vol. III
    (London 1938) describes it on p. 128:

    ?The Bygrave Slide Rule consists of three concentric tubes, the innermost
    carrying a scale of logarithmic tangents and the one next to it a scale of
    logarithmic cosines, both scales being arranged in spiral form. This
    construction is made possible by dropping a perpendicular from X on the side
    PZ of the spherical triangle, as in the Ageton method, and solving the two
    right-angled triangles thus formed.?

    Another description can be found in the 1977 edition of the ?American
    Practical Navigator?, Vol. I, p. 604, in the historically interesting
    chapter on ?Comparison of various methods of Sight Reduction.There is also a
    picture of this slide rule on this page.

    A similar gadget called ?Höhenrechenschieber MHR1? was produced by Dennert &
    Pape in Germany before and during WWII. Although they must have been
    produced in sizable numbers most appear to have been lost during the war
    and/or thrown away as outdated later on; so they seem to be quite scarce
    these days: One ?MHR 1? reportedly was sold on e-bay for $ 1080 a couple of
    years ago. The ?Deutsches Museum? shows a couple of ?Höhenrechenschieber? in
    their new department on ?Computing? (shelf mark 78/255). I could also send
    you a picture of my ?MHR1? off-list, if you like.

    W. Köberer

    Re: Bygrave position line slide rule
    From: zvidoron---COM
    Date: 18 Mar 2004 22:14
    Previous messageNext messageReply to this message

    Hello, Based on the information and images Mr. Koberer kindly sent me and on some details and a drawing from Weems' book Air Navigation I have now built a fully working model of the Bygrave position line slide rule. It is 2-3 times larger than the original and is quite accurate, giving calculated positions to within about 1' of arc (1 nautical mile) with the inputs being Dec, Lat and LHA, so in effect it replaces the normal sight reduction tables. It took some 8 hours of work to make. Do contact me if you are interested in details. Kind regards Zvi

    Bygrave slide rule
    From: wnmpiccer---NL
    Date: 11 Dec 2005 14:00
    Previous messageNext messageReply to this message
    Is it possible to put a drawing/picture of this slide rule on the forum?
     
    I have been looking on the web but cannot find anything
     
    Thanks
     
    Willem Piccer

    Re: Bygrave slide rule
    From: zvidoron---COM
    Date: 11 Dec 2005 13:44
    Previous messageNext messageReply to this message
    I have collected some .PDF files and phographs regarding both the original Bygrave slide rule and its German copy MHR1 (some came from other members of this forum). However, I don't know how they can be posted on the web for all to see - maybe the mediator of the forum has a aord of advice?
     
    I have been toying with the idea of posting a webpage of my own covering the Bygrave and other items of interest to navigators and slide rule collectors but again don't know were to start.
     

    Re: Bygrave slide rule
    From: zvidoron---COM
    Date: 11 Dec 2005 13:44
    Previous messageNext messageReply to this message
    I have collected some .PDF files and phographs regarding both the original Bygrave slide rule and its German copy MHR1 (some came from other members of this forum). However, I don't know how they can be posted on the web for all to see - maybe the mediator of the forum has a aord of advice?
     
    I have been toying with the idea of posting a webpage of my own covering the Bygrave and other items of interest to navigators and slide rule collectors but again don't know were to start.
     












       
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