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Gary:

I got started in cel nav about four years ago. Here's my two bits on
the learning experience. I have a math background and my approach might
not work for you but I was interested in practical cel nav, knowing
what I was doing and why, like Francis Chichester who with a sextant, a
chronometer, an almanac, a pencil and log tables could determine his
position at sea. No computer.  No GPS. No sight reduction tables.

I'm self taught and didn't join this group until a few months ago
though I followed it for  a year before that.  Initially I tried some
of the standard "how to" books including Mary Blewitt's "Celestial
Navigation for Yachtsmen".  Maybe I was just dumb but I found that what
was in essence a set of very simple calculations was hopelessly
obscured in these books by the long explanations of corrections and
interpolations and all the workarounds preparatory to looking up the
solution of the navigational triangle in tables.  Take a look at
Chichester's calculations in the back of his book "Gipsy Moth Circles
the World".  It's really simple!  True, Chichester used sight reduction
tables to save work, but he didn't need them.

One publication I found very useful as a beginner was Bowditch, "The
American Practical Navigator". This is a gem.  I purchased "Norie's
Nautical Tables", and a used 1963 edition of "Burton's  Nautical
Tables" (IMHO far more user friendly than Norie's), both of which
contain the haversine formulas, trig functions, log tables and
haversine tables.  Basically everything else you need to know is in the
back of the almanac.  Over two years I spent many leisure hours
working out numerous examples of the most important kinds of practical
navigational problems which included developing my own work sheets for
each type of problem.  When I was comfortable with manual calculations
I moved on to machine calculations and basically programmed everything
into the Excel application on my Mac following the  instructions in the
back of the almanac.

Meanwhile I was developing practical sextant, charting and plotting
skills, as well as confidence in my results. Ultimately I did buy some
sight reduction tables (Pub 229) and they are certainly easy to use.
But the journey from the haversine formula was great fun and  on the
way believe I learned many important principles.  Last summer I was on
vacation up in the mountains of California and had been shooting some
sights when my son drove up in his new car with built in GPS.  Seeing
my sextant he inquired what I was doing and eyeballed my calculated
position on the chart.  "Let me check your result with my GPS", he
said.  "No", I replied, looking at the GPS result.  "Let me check your
GPS!  See, your position is off by 1.5 miles!"

As others have said, there is a vast amount of expertise and experience
being shared in this group from the very esoteric, to the very
practical.

Welcome to the group and good luck on your cel nav journey.

John Cole


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