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, 17:58 -0700
From: Lu Abel
Date: 2012 Apr 8, 17:58 -0700
You're absolutely right about HO229 being computer generated. In fact the prefatory material gives details.
What I was trying to point out is the ability for the average navigator to directly calculate Hc and Zn using the Law of Cosines on a handheld calculator, whereas previous generations of navigators were constrained to use sight reduction tables of one form or another.
It's off topic, but I just read an Association
of Computing Machinery (ACM) report on the evolution of microprocessors (the sort we employ in everything from our home computers to iPhones to card-key-locks in hotels). The open paragraph gave me a smile: "The first microprocessor, the Intel 4004, was introduced in 1971. In the four decades since, computing power of microprocessors has increased 10,000 fold, enabling complex applications as diverse as climate modeling, protein folding, and computing in real-time the ballistic trajectories of angry birds......"
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all that accurate, but if 2 or 3 decimal places will serve, they won't in celestial nav, slide rules are pretty good "outdated technology".I've had an HP-11C for about 20 years.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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