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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Bowditch Finds Error
From: Russell Sher
Date: 1999 May 10, 02:48 EDT
From: Russell Sher
Date: 1999 May 10, 02:48 EDT
Gordon - I understand that the leap year criteria is dependant on whether or not the (4 digit) year can be divided (or not divided) by 4, 100 or 400 --e.g. if divisible by 100 then it is NOT a leap year (I think) e.g 1900 or 1800 was not a leap year. If divisible by both 400 and 100 - of then overides -- Does someone on the list know more about this?? regards Russell Sher > -----Original Message----- > From: Gordon Talge [SMTP:gtalge@XXX.XXX] > Sent: Saturday, May 08, 1999 8:02 AM > To: NAVIGATION-L@XXX.XXX > Subject: Bowditch Finds Error > > In the first part of the 1984 edition of Bowditch where it tells > about the him and his family, it talks about an error found by > Bowditch in the 13th edition of "The New Practical Navigator" by > Moore, dated 1798. To quote, "The most significant error was listing > the year 1800 as a leap year in the table of the sun's declination. > The consequence was that Moore gave the declination for March 1, 1800, > as 7degs 11mins. Since the actual value was 7degs 33mins, the calculation > of a meridian altitude would be in error by 22 mins of latitude." > > Interestingly enough, I have a copy of the Moore's book dated Jan. 30, > 1798, > unfortunately the title pages are missing from the book, along with his > picture, but the preface states that the book has been through 12 previous > editions. > > I checked the "error" and found that 1800 is not listed as a leap year and > it gives the correct declination for March 1, 1800 as 7degs 33mins South. > > -- Gordon > > > ,,, > (. .) > +-----------------------ooO-(_)-Ooo----------------------+ > | Gordon Talge WB6YKK e-mail: gtalge@XXX.XXX | > | Department of Mathematics QTH: Loma Linda, CA | > | Notre Dame High School Lat. N 34? 03.1' | > | Riverside, CA 92506 Long. W 117? 15.2' | > | http://www.pe.net/ND | > +--------------------------------------------------------+
