Here is my evaluation of several methods of sight reduction.
I learned celestial from Mixter, fourth edition, and this book included a complete reprint of H.O. 211 so this is the first sight reduction method that I learned. I soon bought a set of H.O. 214 and never looked back, H.O. 211 is my least favorite method of sight reduction. Of the _tabular_ methods I much prefer Dreisonstok at this point. (But I am real partial to my Bygrave slide rule.) When my eyes were younger I preferred the Weems Line Of Position Book but I have greater difficulty now using the Rust diagram. Apparently others complained about this because Weems includes a mathematical solution for azimuth in addition to the Rust diagram in the 1944 edition of his book. He made some other changes at the same time. He changed the arrangement of
table A so now each page is entered by latitude not by LHA which adds convenience for working a number of sights from the same assumed latitude similar to the convenience of H.O. 249, H.O. 218 and of H.O. 214 compared to the _inconvenience_ of H.O. 229 (I still don't know why they changed the arrangement and ruined a good thing!) He also changed the size of the book from a handy 10 by 6 inches to a much larger 14 by 8 1/2 inches, not so handy but it does make the printing larger.
So comparing the various standard methods of paper based sight reduction the Haversine Cosine method takes the most work. The Sine cosine method is a little bit less work but there is the problem with logs of negative values of cosine for LHA. Although this method can work with some cases, since it cannot be used in all cases it just makes a navigator's life more difficult to learn both of these methods. (It is
probably the best method to use with a calculator, however.)
I am attaching a list of keystrokes to use in solving this with a calculator. (Note, this corrects a typo in my original posting of the keystrokes so the previous version should not be used.)
All the short tabular methods are more convenient than the previous two.Of the short methods H.O. 211 takes the most work (although it does allow working from the D.R. but this normally doesn't make any difference in practical navigation) followed by H.O 208 and the shortest solution is the Weems Line Of Position Book.
The inspection tables, H.O 214, H.O. 218, and H.O. 249 have the same arrangement of tables and are equally convenient. H.O. 249 volume 1 is especially good when working a round of star sights as you don't need to compute individual LHAs so for this use it is better than the other tables. H.O 214 includes the necessary
factors to allow working from a D.R. but you can also calculate these factors for H.O. 218 and H.O 249 if you need to do this, such as for practice sights from a known location. These tables are only slightly faster than the Weems book. All the inspection tables take up more space on the shelf than the short tables.
H.O 229 is not as convenient as the other inspection tables and requires more interpolations. However these tables might provide slightly greater accuracy for high altitude sights but this probably makes no difference for practical navigation.
 These are links to examples of sight reduction using different methods using data provided by Chichester all from the archives for December
2008.
http://www.fer3.com/arc/m2.aspx?i=106696&y=200812 http://www.fer3.com/arc/m2.aspx?i=106697&y=200812 http://www.fer3.com/arc/m2.aspx?i=106700&y=200812 http://www.fer3.com/arc/m2.aspx?i=106702&y=200812 http://www.fer3.com/arc/m2.aspx?i=106705&y=200812 http://www.fer3.com/arc/m2.aspx?i=106707&y=200812 http://www.fer3.com/arc/m2.aspx?i=106708&y=200812 http://www.fer3.com/arc/m2.aspx?i=106720&y=200812 http://www.fer3.com/arc/m2.aspx?i=106721&y=200812 http://www.fer3.com/arc/m2.aspx?i=106744&y=200812 http://www.fer3.com/arc/m2.aspx?i=106745&y=200812 http://www.fer3.com/arc/m2.aspx?i=106747&y=200812 http://www.fer3.com/arc/m2.aspx?i=106760&y=200812
gl
 On Sat, 1/8/11, Alan <alan202.net> wrote:
From: Alan <alan202.net> Subject: [NavList] Sight Reduction via Daily Pages in NA v.NA Concise Sight Reduction Tables To: NavList@fer3.com Date: Saturday, January 8, 2011, 9:11 PM
Given that my efforts at Celestial Navigation are limited to, and unlikely to progress beyond standing on the beach, when I can get there, shooting whatever happens to be in view, day time and or evenings, it doesn't make a whole lot of difference, however I learned to do sight reduction using the NA Daily Pages and the Law of Cosines, which strike me as a simple to use, direct, straight forward approach to sight reduction. Lately, I have begun to delve into use of the NA Concise Tables, a Power Squadron Nav course I'm taking requires reduction of sextant sights by both methods. I understand that the Concise Tables Method are supposedly simpler, easier to
use. Perhaps they are, doing the Law of Cosines absent a calculator, using log tables would be tedious as hell, however as to the Concise Tables being "simpler/easier to use", I beg to differ, for it seems that the Concise Tables involve endless messing about with and or the massaging of numbers, which one doesn't have to do using the Law of Cosines. Of course, I might be missing a salient point perhaps more than one here, for instance what happens if one's calculator craps out. Of course, with the Concise Tables, one would be out of luck if they lost their NA over the side. Seriously though, is there something basic or obvious here that escapes me? In appreciation of any input or clarification offered. Alan  NavList message boards and member settings: www.fer3.com/NavList Members may optionally receive posts by email. To cancel email delivery, send a
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