NavList:

----- Original Message -----

From: Brad Morris

To: enoid@northwestel.net

Sent: Wednesday, April 03, 2013 8:07 PM

Subject: [NavList] Re: Which Method do you prefer using and why.

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In answer to the question, for non-electronic means, the Bygrave and its variants (including Gary's Flat Bygrave) are fast and accurate.  Also small and light.  Works from the equator to the poles.  Certain singularities are to be avoided.

If its to become a list of table solutions, here's one not often discussed here:
"HO203 The Sumner Line of Position furnished ready to lay down upon the chart by means of tables of simultaneous hour angle and azimuth of Celestial Bodies; Lat 60N to 60S ~ Declination 27N to 27S"  (My copy 1923)

and

"HO204 The Sumner Line of Position furnished ready to lay down upon the chart by means of tables of simultaneous hour angle and azimuth of Celestial Bodies; of Celestial Bodies between 27 and 63 degrees of declination Latitude 60 N to 60S" (my copy 1933)

+++++
There's 9 volumes of HO214 taking you to 89 degrees of latitude.  A might weighty set indeed.  The 79 to 89 degree volume is the hard one to obtain.  No one ever really had a need for it.

Brad

On Apr 3, 2013 7:18 PM, "Lu Abel" <luabel---com> wrote:

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I totally agree, Frank.  In my comments I was just trying to differentiate between learning history (or entertainment) and eschewing reasonable ways of solving "where am I" because of a mistaken belief that they're somehow unreliable.  HO 229 is great -- in the context of its history.   Ditto HO 249.  And HO 208, and haversines, and lunars and ....

Speaking of which, about three decades ago there was a Brit (who else?) sailing around the world in an open 18' boat.  One day he got rolled and lost much of his supplies including his toilet paper.  But not his nautical almanac.   From there until his next port of call, there was a race between his sanitary needs and his navigational needs.  

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From: Frank Reed <FrankReed---com>
To: luabel---com
Sent: Wednesday, April 3, 2013 3:27 PM
Subject: [NavList] Re: Which Method do you prefer using and why.

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Lu, you wrote:
"Another thing that is often overlooked is the cost. I purchased a solar-powered scientific calculator ("if you can see the numbers, it's getting enough light to run," no need for batteries) for $10 over a decade ago. A copy of HO 229 for a single band of latitudes costs more than twice that, and you need HO 229 for six latitude bands (okay, lets be practical, few of us will sail north of 60 deg, so maybe only four). So I could hermetically seal a half dozen of these calculators and store them in a protected location for less than the cost of the four copies of HO 229."

Excellent points. Basic scientific calculators are just darn cheap. And they're really resilient to many types of damage. And they're also easily replaced. Luis Soltero, author of the Starpilot software which runs primarily on a programmable calculator, made the point some years ago that you can replace a calculator literally ANYWHERE on Earth. It's not like it was thirty years ago. Every so-called "third world" country has office supply stores stocked with the same basics as we find in the economic "first world" including standard scientific calculators.

From my perspective, a good reason to learn tables is entertainment value. That may sound frivolous, but it shouldn't be overlooked. We stay in practice when we enjoy the process. If tables, even as peculiar as "Martelli's miracles", make you happy and help you stay in practice, then that's half the battle! Go for it. I find that many people stay interested by learning new tables that really offer no actual practical benefit but there's a pleasure in the process. It's more than mere stamp-collecting, more than merely adding another H.O. "badge" to the list.

-FER

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