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Celestial Navigation Pac (DaVinci Technologies/Sparcom) Back

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Product Celestial Navigation Pac
Manufacturer DaVinci Technologies/Sparcom
MPN (Manufacturer Part Number) 10121-1A F
MSRP $199.99

Sku: 10121DT1AFU
Condition: Used - Very Good
Our Price: $199.99
Weight: 0 /lbs. *Free shipping
Availability: In Stock (1-2 business days) 

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Includes card only; 90 day warranty on 2nd hand products.
Product Summary   
The Celestial Navigation Pac is an ultra-fast, easy to use, plug-in card for the HP 48 GX/SX, and an invaluable aid in performing celestial navigation calculations in a portable environment. Designed by experienced navigation specialists, this "plug and play" software offers speed, accuracy and ease of use. The Celestial Navigation Pac is designed to remove the drudgery of sight reduction so you can appreciate the joys of navigation by the stars. Main Features
Product Description

Main Features

Celestial Navigation Pac contains several menu-driven applications that allow you to:

  • Compute position fix from two or more celestial observations.
  • Plot lines (circles) of position.
  • Estimate position from single observation combined with dead reckoning.
  • Compute running fix, accounting for the motion of the observer.
  • Compute course and distance for rhumb lines and greater circles.
  • Refer to a built-in accurate and complete astronomical almanac.

Navigation Tutorial

An extensive Navigation Tutorial in the manual leads you step by step through a voyage from San Diego, CA to Honolulu, HI. A detailed example introduces issues such as dead reckoning position at the beginning of a voyage, route planning , inputting celestial observations, entering sun sights, position fix, running fix, evening star sights, moon/planet fix, and dead reckoning as third observation. Corrections for sextant observations use atmospheric pressure and temperature. Route planning helps compute the course via rhumb line and great circle routes. One can take advantage of evening star sights from the built-in Almanac program.

A short and a long list of stars, as well as a list of Greek letters and a list of constellations are included in the application. The stars are represented by their "Bayer designation".

Data Editor

In a special directory all the navigation data is saved under simple variable names specified by the user. The data editor in saves observations in a user-friendly file for later access.

The Running Fix

Is computed from observations widely separated time, obtained when the vessel is moving. Two built-in programs, (ADDOB and ADV), tackle the task of computation using different methods. By selecting a time when the fix is valid, the ADDOB program will automatically advance or retard all observations to this time, yielding a running fix. The ADV program advances the observations by correcting the Greenwich Hour Angle and the declination of the observed body. This correction depends somewhat on the position, and hence current dead reckoning position is used.

Two kinds of errors commonly encountered in navigation are analyzed in this Pac: random and systematic. To minimize random errors, the user is encouraged to take a number of observations so that a least square fit analysis can be used to compute random errors. Systematic errors are minimized prior to the start of any voyage by taking observations from a known location and comparing the celestial result with your own true position. If there are no systematic errors, the uncertainty in location of the position is 0.25 nautical miles.

The Sailings

The SAIL program computes the course and distance of a voyage using the rhumb line, great circle or composite route. A great circle route does not follow a constant course; the courses are "true" and not "magnetic". A great circle route can be planned in a series of short rhumb lines, by setting up a series of waypoints. The program can compute the vertex of the great circle. Composite route planning allows a combination of great circle planning and placing limitation on latitude beyond which the user does not wish to sail.


The Pilot program allows dead reckoning, distance off by vertical angle, distance off by two bearings, current set for drift, tide interpolation, true course versus magnetic course, and a distance/speed/time calculator.


Eighty-nine stars are listed in the pac, using their Greek abbreviations.

The Celestial Navigation Pac comes with a very handy manual that includes a quick reference section for sight reduction and running fix, a quick reference guide for the menu structure used in the pac, an extensive glossary, and a set of frequently asked questions. The Celestial Navigation Pac was developed by an expert sailor while working at the University of Hawaii.

Additional Information   
Suitable for HP48SX and HP48GX


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