A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Position-Finding
From: Robert VanderPol II
Date: 2017 Mar 19, 07:11 -0700
Pepperday's S-tables (9pg) are a version of Ageton's HO-211 (36pg).
Pepperday cuts the table length in half to 18pg by reducing the accuracy from 0.5arc-min to 1.0arc-min and then in half again to 9pg by use of column headings across the bottom to eliminate repeated table values. The table values repeat from front to back but under the opposite heading,
I beieve Pepperday uses a slightly rearranged worksheet flow compared to HO-211 to use t intead of LHA.
All of the variants of HO-211 including Bayless suffer from reduced accuracy (up to 30 arc-min) when t/LHA or K (an intermediate value in the reduction process) approach 90o. This is a result of the sight reduction process being a step function rather than a continuous function. The 2nd edition of Bayless includes the Sadler technique for use near 90o but there is still a significant band of results with reduced accuracy, just not as bad as originally.
The accuracy problems and the time involved in the reduction process is why HO-211 fell out of favor with the military Pre-WW-II who then developed faster and more consistently accurate methods, HO-249 and HO-229.
If you can accept that you will need to throw away sights with t/LHA or K near 90o then HO-211 and it's variants are a good choice where a compact table is a premium need. Also it is the only system that uses your EP rather than a different AP for each celestial body which makes plotting easier. Actually I think some of the systems using tables of mathematical functions allows use of EP but I'm not sure which and they aren't used in pactice much.
Re: S-tables: where to have a look at them?
From: Tony Oz
Date: 2017 Mar 19, 02:54 -0700