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Subject: Re: Celestial Calculator Comparisons
From: Dan Allen (danallen@XXX.XXX)
Date: Fri Mar 10 2000 - 12:12:46 EST
There is a spectrum of celestial nav possibilities:
a) GPS - push a button, get an answer - easiest thing going, but depends
upon 24 satellites above, along with a support infrastructure on the ground.
Fix in 15 seconds.
b) Sextant & calculator - not as handy, but fully self-contained. The
calculator needs power, but if you have a solar battery charger and 3 AAA
nicads, you could run an HP-48 for a long time... Fix in a few minutes.
c) Sextant & slide rule or HO 249 or paper - no energy concerns at all;
works in all climates and temperatures, fully self-contained, and gives the
navigator something to really sink his teeth into. Fix in 15-30 minutes.
I believe that we need to be skilled in all three. One solution that has
helped take the drudgery out of the last option for me is to write my own
celestial nav software on my HP-48GX. This has kept the principles and
concepts clear in my mind so that I can play with the basic formulas and
feel comfortable with them in case I did need to go the option C route
above.
Dan Allen
danallen@XXX.XXX
Navigate | Calculate | Communicate > Set Sail!
-----Original Message-----
From: Navigation Mailing List
[mailto:NAVIGATION-L@XXX.XXX]On Behalf Of Joe Shields
Sent: Friday, March 10, 2000 8:01 AM
To: NAVIGATION-L@XXX.XXX
Subject: Re: Celestial Calculator Comparisons
As a landlocked armchair navigator who dreams of one day moving beyond my
little 1 nm wide (at its widest part) man-made lake and out into blue water
where I could do celestial nav. for real, I may be naive, but I am confused
by all this concern over celestial calculators. Wouldn't regular use of an
'electronic' celestial calculator defeat the whole purpose of celestial
navigation -- a reliable alternative/backup to 'electronics'. Doing sight
reduction by hand (in both my opinion and the opinion of the ASA Instructor
who certified me) is a volatile skill that needs to be practiced regularly
to be reliable. What you don't use, you lose... which could be everything
from your copy of HO 249 (or whatever) to doing accurate mental arithmetic.
Is my thinking wrong that the best discipline is that my daily navigation
would consist of doing traditional 'non-electronic' celestial/coastal/DR
navigation to arrive at my position and then check it against the GPS. With
everything in close agreement, my comfort-level would be such that any
'electronic' outage would not give rise to panic or drastically alter my
navigational routine.
Or is it more realistic that you are busier than a one-armed paperhanger,
and you need all the shortcuts you can get.
-- Joe Shields (lat:40 34, long:80 04)
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