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Gentlemen,

I came across the Complete On Board Celestial Navigator shortly after
becoming interested in celestial navigation. I knew a little but not a lot
about the subject when I first looked into George Bennett's book, after
teaching myself from Susan P Howell's book. While the latter is an excellent
primer it should not be compared to Bennett's book - they seek to do two
different things.

Using Howell's book the navigator will still need to invest in and carry a
current nautical almanac and set of often multi-volume tables such as HO
229. This is both expensive and bulky for yachting use. The great benefit of
the Bennett book is that it is all there in one compact, light and cheap
offering. The only sacrifices made are a slight loss in accuracy -
negligible - and a need for limited interpolation.

Bennett makes clear at the front of his book that it is intended as a backup
for electronic methods of navigation and that it was prepared primarily with
an eye to convenience and cost and I think it fills those aims admirably.

But the really outstanding feature of this book is his table of change of
altitude of a celestial body for any Z and lat over 5 minute intervals. This
enables easy averaging of sights without maths. This is something that I had
not seen published anywhere else in navigation textbooks and I mean anywhere
else stretching back to Raper and Norie in the nineteenth century. I use
Bennett's tables constantly to check sextant sights for accuracy and
eliminate personal error. If nothing else, the book is worth the cover price
for access to these techniques.

So for anyone interested in the science/art/practice of celestial navigation
Howell and Bennet are both very worthwhile investments.


Kieran Kelly

   

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