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    Re: Traditional navigation by slide rule
    From: Paul Dolkas
    Date: 2016 Jan 11, 21:43 -0800

    The 5” aluminum Pickets were the ones they flew in the early Apollo days.


    Oh, and speaking of space, here’s a shot of the sextant they flew late in the Gemini program. (Gemini 10, I believe) Didn’t work out very well – they often had trouble discerning the true horizon from high cloud layers. Internally, it’s a two mirror design, more akin to a nautical sextant than an aircraft type.  The astronauts were given tables and worksheets so they could work out rendezvous calculations by hand as a backup method to using the on-board computer.  (No Bygraves  or anything else of the sort.)  

    Michael Collins writes about the trouble he had with all of it in his book “Carrying the Fire”.


    Paul Dolkas


    From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Alan S
    Sent: Monday, January 11, 2016 8:05 PM
    To: paul@dolkas.net
    Subject: [NavList] Re: Traditional navigation by slide rule


    As has been mentioned, there were "corrosion problems", I have no idea of what sort or of why, with the magnesium metal or alloy slide rules, which were eliminated or avoided with the aluminum alloy slide rules they went to later on. I had 2 Pickett slide rules, one a 10", rather basic type I believe, now in the hands of a nephew, and a fancier 5" model that somewhere along the line, went lost, or possibly ended up in the hands of someone who saw it, and couldn't resist the temptation. Of course, I might have simply misplaced the thing. The 5" rule, as I remember, tended to be "sticky", not at all the case with wood body rules. I've heard some people speak very highly of the Pickett rules, though frankly I never had that much experience with them. Of course, while they still work as well as they ever did, batteries not required either, slide rules, "stick" or circular, are curiousities today, as might be the case tomorrow or the day after with electronic calculators that are all the rage these days. Brighter heads than I can only guess.



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