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## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

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Re: Bowditch 2002
From: Mitch B Burrill
Date: 2002 Oct 3, 16:17 -0400

```The only algorithms I know are :

1. Always round up, like a modern electronic calculator (which I think leads
to serious error accumulation in hand calculation)
2. Round up if the digit to the right of the 5 is odd (or even)
and 3. Round up to make the digit to the left of the 5 odd (or even).

To get the values below (which are published in Bowditch 2000 AND the 23rd
edition of the CRC math tables),
Bowditch is using Round if Right is Odd.
But then that algorithm fails with the published values for 32-22 and 32-33.

I'm stymied (for now)  !!
-----Original Message-----
From:   Herbert Prinz [mailto:hprinz@ATTGLOBAL.NET]
Sent:   Thursday, October 03, 2002 3:01 PM
Subject:             Re: Bowditch 2002

Well, Mitch, which rounding algorithms are you aware of?

Sin(32d 07') = 0.53164497... and Sin(32d 43') = 0.54048508...

So, rounded to 5 places after the decimal point, we would expect to see
0.53164 and 0.54049, using ANY rounding algorithm that I can possibly think
of.

What does Bowditch have?

Herbert Prinz

Mitch B Burrill wrote:

> Yes, examine the sine of  32-07, 32-22, 32-31, 32-33, 32-43, and 32-59. The
values given for 32-07 and 32-43 seem mutually exclusive using the rounding
algorithms I'm aware of.

```
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