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    Re: Bygrave formula
    From: Hanno Ix
    Date: 2014 Jun 29, 16:06 -0700
    Francis, Oerjan, Brad,

    Thanks for the info!

    When you look closer at Tina's cylindrical CelNav ruler you'll see it's not a Bygrave.
    In the picture the lines go from left to right, not around in a helix. So it is a cylindrical version
    of G.LaPook's flat Bygrave, so to speak. Interesting!

    I've never thought of this idea. I am pondering if her version can reach the genuine Bygrave's
    resolution and if the mechanics are simpler than the Bygrave's - provided it is optimized version in this regard.
    What do you think?  I'll will try to reach her for copies of her scales.



    On Sun, Jun 29, 2014 at 9:36 AM, Brad Morris <NoReply_Morris@fer3.com> wrote:


    You may wish to obtain your scales from Robin.  He spent an enormous amount of energy getting each of the tick marks to be identical to the German MHR-1 in my possession. 

    That is, of course, should you wish to use that scale!


    On Jun 29, 2014 1:57 AM, "Francis Upchurch" <NoReply_Upchurch@fer3.com> wrote:

    Thanks Hanno,

    No ,I was not aware of Tinas’s work.

    Looks good and simple. I used Gary’s scales for my first prototype some years ago and later Wayne Harrisons “authentic” looking scales for my Fuller 2 and Bygrave “replicas”. My latest minifuller 2 uses a condensed form of Wayne’s  Fuller 2 scales, but I have added cosine numbers in red and green going the other way. (can do that with photoshop 7, which is the only software I have. The original Wayne scales were done on postscript I think. ! think Wayne will send me new ones with only cosines when he has time. Meanwhile, I’m finding the new minifuller2 prototype with red/green cosines works perfectly with magnifiers .the brake prevents slippage which was a source of un-noticed error.(my Bygrave, made in a similar way, without a brake does not slip. All down to correct maintenance of the felt strips))  It amazingly seems nearly as accurate as the full sized original (4-7 places) and easier/quicker to used because of the Otis King type format. I’ll send comparative results, also describing the moves, maybe end next week if I get time.

    So far, my favourite is the Bygrave for LOPs in range of the scales, then the minifuller2 for all cosine type formulae, including lunars. The big Fuller 2 replica is great for shore based work ,does  not need magnifiers,  but would also double as a useful weapon to repel pirates who, you may know, infest the waters around my home in  Penzance!

    Tina may want to update us on progress? Looks interesting.

    Best wishes



    From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Hanno Ix
    Sent: 28 June 2014 23:56
    To: francisupchurch---.com
    Subject: [NavList] Re: Bygrave formula



    here is a a very good article I found on the www:

    Tina's Bygrave Position Slide Rule.

    I could not found anything else by her or about her.

    Do you know more about her work?
    In particular, I'd like to see her scales in detail.




    On Tue, Jun 10, 2014 at 1:46 AM, Francis Upchurch <NoReply_Upchurch@fer3.com> wrote:

    For those who prefer the old, full sized Fuller 2, here are the intructions for LOPs. Also some pics of the new prototype mini fuller 2, in the style of the Otis King.(2 copies of the main scale.One log sine scale + curser with top (L) and bottom (S) as per the Bygrave and Otis King.(pics of old Fuller, Otis King, Bygrave for comparison) Can do everything really, much faster than the old Fuller and so now plastered in tables/long term almanacs/formulae etc . Notice the anti-slip "brake" ,similar to Gary LaPook design. Tighten the wing nut at the top, sqeezes the rubber washer made from my old sphygmomanometer (like me, recently retired!) rubber tubing, which expands easily, forming a brake against the inner cylinder. Needs watch makers lenses for accurate reading of the condensed scales.

    The build details similar to all the others. Happy to supply more details on request. 

    Still prefer the Bygrave for most things, but not so good at Lunars. Cannot handle difAz angles greater than 900 so have to use the mini Fuller2.

    Sorry for the recent outburst of postings! Out of action soon for a while in hospital, but will be keeping up with what you good folks are doing with great interest!

    Frank, any more thoughts on your BRILLIANT  "verticle circle collapse method"? 

    Best wishes to all and thanks for the fun.


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