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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Lunars using Bennett
From: Peter Fogg
Date: 2008 Apr 4, 19:29 +1100
From: Peter Fogg
Date: 2008 Apr 4, 19:29 +1100
Alexandre you wrote: > The tables in Bennett do not have sufficient > accuracy ... because they are > rounded to 1'. > ... and the errors will accumulate). Firstly; these are not 'errors', which implies inaccuracy, but rather a limitation in precision. Secondly; the amounts by which the values are rounded up or down, when added together (as they are in Bennett) will NOT tend to accumulate, but will tend to cancel each other out, and trend towards accuracy, rather than inaccuracy. In Jan 05 I tested this and presented the results here: http://www.fer3.com/arc/m2.aspx?i=021346&y=200501 and then, in: http://www.fer3.com/arc/m2.aspx?i=021372&y=200501 summed up the chances of all 6 rounded values accumulating towards inaccuracy, rather than tending to cancel each other out, as: "... the chance of that most unlikely event is one in six to the power of six, or 0.00002, or [happening, on average, in] 0.002% [of cases where there are 6 rounded values added together]". Finally, the issue I take exception to here should be clear enough - it is limited to this strange yet persistent notion that the amounts by which values are rounded will tend to accumulate in series. I have no opinion about using Bennett for lunars, other than to congratulate d walden on the ingenuity of the idea. --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---