NavList:

There you go Frank! as I think you folks say.You are spot on, go for it as we say here. You are correct in using the words obsolete and insane in connection with my Bygrave lunar thing! My wife uses stronger Anglo Saxon terms!(relax, I use GPS and chart plotter to check my celnav when at sea with "normal" crew.)
Yes, the Bygrave gives accurate (so far spot on and not 1' out, but only a couple of clearances so far) LDo if starting with known RBA (sorry, Az differences as you corrected me.)It is just the first calc I cannot do. I've tried "going backwards" but always get stuck at an unknown such as "y" or Az or RBA (Azdif).
Just eyeballing the triangles page 84 John Karl's book,it looks to my non mathematical eye to be "Bygrave" territory." I can do the bottom one fig 8.2(b) to get LDo using Ho,ho and RBA(azdif).I just need the first bit, ie unknown RBA (Azdif)(or possibly "y") from known Hsd, hsd and LDsd.
Anyhow, thanks for pushing the game along, no matter how insane!
I'm confident it can be done! My simple brain understands pictures of triangles better than maths, which I know is not good for this celnav/slide rule interest.
Best wishes
Francis
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