NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Bowditch sightreduction table (Ageton?)
From: Lu Abel
Date: 2012 Apr 8, 18:12 -0700
From: Lu Abel
Date: 2012 Apr 8, 18:12 -0700
Your comments about slide rules reminds me why so many (especially on this list) are more comfortable with celestial than with GPS. With celestial navigation we enter a series of numbers from the NA and our own environment (ie, Lat, Long, and time) and we can see those numbers evolve step-by-step into a line of position. With GPS, the magic happens inside the black box and all you get is a pair of numbers. It all depends on how much we trust the programmers of the black box to get it all right.
BTW, anyone remember back in the 1970s when Texas Instruments shipped a scientific calculator that output "1" for the sine of 0?? (every other sine calculation was correct, just sine of exactly zero degrees was totally wrong)
From: Alan S <alan202@verizon.net>
To: NavList@fer3.com
Sent: Saturday, April 7, 2012 7:31 PM
Subject: [NavList] Re: Bowditch sightreduction table (Ageton?)
Lu Abel:Re your last, corrrect me if I'm wrong, but HO 229's tables were computer generated. HO 214's tables were "calculated" using log tables or who knows what. As to your referencse to "calculators", sounds right to me.As to slide rules, I hadn't so much as looked at one in close to 50 years, I used to use Smoley's Tables at work, until I saw some posted comments on doing SOME sight reduction calculations with a slide rule. I ended up buying a couple on ebay, and play around with them now and then.Someone once offered, re slide rules, "if the answer looks wrong, it likely is wong". They aren't all that accurate, but if 2 or 3 decimal places will serve, they won't in celestial nav, slide rules are pretty good "outdated technology".I've had an HP-11C for about 20 years. Greatest thing since "sliced bread", or words to that effect.
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