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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Compact H.O. 211 (Ageton-Bayless) question
From: Stan K
Date: 2016 Jul 16, 18:40 -0400
From: Stan K
Date: 2016 Jul 16, 18:40 -0400
Not sure if that is really the reason for the tenths, but it is the best I've heard.
In any case, apparently I had already agonized over this issue. I found this statement in the Celestial Tools Help, which has been there since V4.4.0, over two years ago:
Both the compact and original versions have most of the tabular data rounded to the nearest whole number. However, the compact version shows
values below 166 to one decimal place, and the original version shows values below 239 to one decimal place. The example in the compact version
shows one of these low values rounded to a whole number, but an example in the original version uses the tenths. However, Celestial Tools will abide
by the USPS rules for the compact version: "Record all decimal values exactly as shown in the Compact Table. Do not round to the next whole number.
Carry all decimal values forward and use for all computations."
So I guess I'll be sticking with those "rules" after all.
Stan
-----Original Message-----
From: Robert VanderPol II <NoReply_RobertVanderPolII@fer3.com>
To: slk1000 <slk1000@aol.com>
Sent: Sat, Jul 16, 2016 12:39 pm
Subject: [NavList] Re: Compact H.O. 211 (Ageton-Bayless) question
From: Robert VanderPol II <NoReply_RobertVanderPolII@fer3.com>
To: slk1000 <slk1000@aol.com>
Sent: Sat, Jul 16, 2016 12:39 pm
Subject: [NavList] Re: Compact H.O. 211 (Ageton-Bayless) question
It just occured to me why the Ageton tables include the first decimal for some values of A & B. It is to make interpolating easier if the user decides to do so. When the values are the same for 2, 3 or more angles in a row it is harder to interpolate, by adding the decimal you only need to work with 2 numbers rather than 3 or more for the interpolation to be accurate. For the rest of the range where values are reported with no decimal, when you start interpolating, you are dealing with only the values to either side of the intermediate angle you want so the interpolation only involves 2 values.
In normal use round the decimals to the nearest whole number.
When you start interpolating the angles decimals become significant for some of the value so having decimals for some of the table values eases the interpolation process.
