CD-Sextant - Build your own sextant - Pole Shift Survival Information

Navigator Light Software
Source: Navegação Astronômica e derrotas
Artificial Horizon
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If you live in a city far from the sea, you can't take altitudes of celestial bodies with a marine sextant, because you can't see
the sea horizon. One way to work around this problem is to use an artificial horizon. The artificial horizon can easily be
made with a plate filled with liquid. Water will do, but oil is better. The surface of a pool can also be used, if there is no
wind or waves (the water surface must be completely flat).
To take the altitude with the artificial horizon, point the sextant towards the
artificial horizon and make reflected image of the celestial body coincide with the
direct image. The angle you read is twice the altitude of the body, as illustrated in
the figure below.
Also read the index error.
Navigator automatically corrects for the use of artificial horizons:
● The program divides instrumental altitude by two. Enter sextant reading directly.
● The Dip and semi-diameter corrections are set to zero.
● The index error is also divided by two.
Printing Nautical Almanac Pages
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Navigator (registered version 2.5 or latter) has a Nautical Almanac page generator/printer. These pages are not exactly the
same as real almanac pages, but they contain most of the information needed to do celestial calculations in the traditional
way, without the computer.
Navigator generates the so-called "daily pages" (the ones with 3-day celestial data for planets, stars, Sun, Aries and Moon).
The yellow ("increments") pages are not generated because they don't change from year to year. You can use the yellow
pages of an old almanac or do the interpolations with a pocket calculator.
I choose to make the Navigator daily pages as similar as possible to actual almanac pages. But there are differences:
● Did not include the latitude dependent tables (Twilights, Sunrise, Moonrise, Sunset, Moonset).
● Did not include the Aries meridian passage time. This number is used to calculate the meridian passage of stars, and is
seldom used.
● Did not include the Sun's Equation of Time and meridian passage table. You may use an old almanac for the Sun's
meridian passage calculations, as these tables are almost unchanged from year to year. Just use the table of the same
day.
● Did not include the Moon's meridian passage and age table.
● Did not include the planets' SHA and meridian passage table.
● Added three stars not included in most Nautical Almanacs
I plan to include some of these numbers in future versions. Feedback from users about what features are most important is
welcome.
If you compare the Navigator's almanac pages with nautical almanac pages, you will note small differences in the numbers.
These are caused by different celestial calculation methods and should not be bigger than 0.5'. This error is small when
compared with other imprecisions that affect celestial navigation, and will not impact your position significantly.
Printing the almanac pages
To print almanac daily pages, do:
1. Go to the celestial navigation window.
2. Select the "Other calculations" tab.
3. Press the "almanac pages" button. The "Almanac Pages" window will show.
4. Set the initial date for the 3-day page.
5. Select "Aries and planets" (left side page).
http://www.tecepe.com.br/nav/navpro.htm (10 of 23) [9/2/2004 11:05:07 PM]