|
|
From: Peter Fogg (no email)
Date: Tue Dec 06 2005 - 16:20:00 EST
There certainly were a lot of old-fashioned methods, Jim. Tables were useful
to allow computation of the navigational triangle, and apparently some List
members still prefer to use a slide rule, possibly because they are familiar
with it and it gives a result appropriate for their needs.
However, a few decades ago the small, inexpensive electronic calculator was
introduced. With it and appropriate formulas a precise result can be quickly
and directly produced. Tables and slide rules still have the advantage of
not needing batteries, as well as being less liable to the corrosive effects
of on-board life.
Having said that, there is a lot of interest on the List in the history of
navigational methods and instruments, and in the past various books,
websites, etc have come up for mention. Thus there is a wealth of
information within the archives of the List, apart from whatever responses
you may get directly.
Happy hunting
_____
From: Navigation Mailing List [mailto:]
On Behalf Of Jim Hickey
Sent: Wednesday, 7 December 2005 7:47 AM
To:
Subject: Alternate methods of sight reduction
Alternate methods of sight reduction
First, allow me to introduce myself as a new member. My name is Jim Hickey.
My wife Judy and I currently live aboard our sailboat in St. Augustine,
Florida. I have been interested in celestial navigation for many years much
to the amusement and entertainment of my wife! Even got the programming bug
early on but have it under reasonable control at this time. It has been a
delight to read many of the fascinating postings for some time now.
I have a volume of Bowditch that discusses a variety of sight reduction
methods. I believe all the old table methods and more have been discussed.
Has anyone had access to or knowledge of the old slide rule type method that
is referenced? I believe the instrument was called a Bygrave computer which
looked cylindrical.
As well, there is also a picture of a wonderfully elegant looking globe like
device that is set up with sliding arms that solves the navigational
triangle directly.
I have been intrigued by these items for years and of course would love to
mess with them if I had the chance as I am sure many here would.
Very curious to know how effective these approaches were and if there are
others etc. etc.
Cheers,
Jim
|