## IntroductionThe section on Celestial Navigation originally
was the main page on this web site.
As a consequence, this part of my web pages has some older parts,
which are not yet completely 'integrated' in the rest of the documents.
Since my interest is primary on the practical side of Celestial
Navigation, the more theoretical issues are not at all or only
basically covered.
Some of this basic material is quoted from other web sites.
When using quoted material this is explicitly mentioned including
the web links I used to obtain that information.
However, since most of this material is already more than ten
years old - which is a rather long time in the Web - some of these
links may be outdated! ## Project Development## Nautical AlmanacThe first part of the project was the
Nautical Almanac, which is based
on the ephemeris data available from the Jet Propulsion Laboratory
at the NASA. The driving idea to make a Nautical Almanac
available from an internet server, was that many hobby sailors
like myself, are practising Celestial Navigation for only a
couple of days or weeks a year. From this site the Nautical Almanac is available in two forms: - an interactive form supplying the Almanac Data of one (selectable) celestial body for 6 successive days in HTML format
- a compiled form of the Nautical Almanac for a complete year as PDF file (ca. 1.5 Mbyte). This Nautical Almanac can now be downloaded in 5 separate parts to reduce web traffic and save transfer costs. See the "Download Section" for more information.
## Interpolation TablesThe Interpolation Tables
available here are designed to be used for both interpolation of the
Nautical Almanac data (GHA and Declination) as well as for the
interpolation of the data from the Sight Reduction Tables (Altitude).
In order to obtain the highest possible accuracy, I decided to use a
logarithmic numeric method for interpolation. ## Correction Tables for Sextant AltitudesThe next step was to find the formulas and
mathematical models for the corrections, which have to be made
on the measured altitudes in order to align these measurements
taken from the real world with the calculated data obtained
from an idealized mathematical model of the universe used for the
Nautical Almanac. ## Sight Reduction TablesFinally, I included the
"Sight Reduction Tables" to determine
calculated altitudes without having to use an electronic calculator. ## Source codesThe codes of the programs used for generating
the Ephemerides of the Nautical Almanac as well as the program
used for generating the Sight Reduction Tables can be downloaded
for personal use. - the NOVAS subroutines
- the program codes of David Hoffman for generating and manipulating the binary ephemeris file(s)
- my own source codes for Nautical Almanac, Sight Reduction Tables, Sextant Correction Tables and Interpolation Tables.
The package is called CN_code.tgz and comes as a "gzipped-tar-archive" (850 Kbyte). More information on how to extract this archive and on compilation of the C-code is available from the "Notes on the C programs used to calculate the Ephemerides". ## Terms of UsageThese Web Pages do not pretend to be a complete
guide to Celestial Navigation.
The principal purpose of these Web Pages is to serve as my personal
source of information for practising Celestial Navigation.
I would of course enjoy it very much if other people interested
Celestial Navigation may find some useful information here. |

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