# NavList:

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

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Re: Out of Date Almanac
From: Gary LaPook
Date: 2009 Dec 08, 22:11 -0800

```For using just the stars you can just  memorize the GHA of Aries for
0000Z December 31, 2009 which is 99� 33.4', and remember that Aries
advances 59.139' per day. Then looking at a calender, or daytimer
(preferably one that shows the number of the day of the year ) or
figuring out the day's number ("thirty days have November ...) in your
head, you can multiply 59.139' times the number of the day of the year
and add this to 99� 33.4' to find GHA Aries for 0000 Z. The reason to
use December 31, 2009 instead of January 1, 2010 as the starting point
is that January 1 is day 1 of the year. If you start from January one
then you must subtract one from the day of the year number to show the
number of days that have elapsed from the starting point, starting on
December 31 avoids this extra step. Then compute the increment for GHA
Aries for the time of day at the rate of 15.041� per hour.

If you have memorized the SHAs and declinations for a few stars you will
have all the information you need to compute the Hcs for a stellar fix.

Or, if you don't trust your memory.

Just rip out the left hand December 31st page from your N.A for 2009 (or
zerox it), which contains the GHA Aries for 0000Z and the list of star
positions, and write along the bottom of the page "59.139' per
day----15.041� per hour" and then you can compute the Hcs for your star
fixes for a year to an accuracy of better than one minute of arc.

gl

Greg Rudzinski wrote:
> Any opinions on using a Nautical Almanac that is four years out of
> date? I bring this up because there are old almanacs available on
> Amazon.com from \$2 to \$10.  New Nautical Almanacs have gotten
> expensive so my plan is to use a 2006 for the upcoming year 2010.
>
>

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