NavList:

Thank you so much Greg,

I did not know about the 8 inch Weems circular.Please send details. Must have one of those if available! Very interesting. I was thinking of building a 12-14 inch" Poor LOP" circular rule(circa 1915), but have not had the time.This uses the haversine. Maybe in the winter.I'm almost changing my mind about the original Fuller 2 replica. Not very sea worthy,(but neither is the sextant!!) but unbelieveably accurate,(5-7 places, so as good as a calculator) and now I have cosines,very quick for all cosine formulae. This has been around since late 1800s so surprised no record of use for cel nav then. Let's keep up this very interesting debate. Good subject for beached, couch- bound invalid cel nav/slide rule  nutcase! PS Still not sure advanages of haversine versus versine long hand methods. Look the same to me. I have just got  perfect copy of Norries tables for £3 from amazon off- shoot. (circa 1980s) and can now do both. Brilliant. Can't understand why these not used and short tables were.(ww2 and why not Bygrave, even quicker and easier?) I find Versine long hand quicker and better than short tables, and I understand what we are doing, which is good for me. Bygrave still fastest for me (LOPs), but Fuller2 better for lunar clearance.

Best wishes

Francis