Navigator News
JUN/01/2006 - Navigator service pack released

Navigator 4.5 (build 151) Service Pack 1 was released today.
This is a service release but there are some new features as well.


  • fixed a problem in meridian calculation.
  • fixed program crashes while printing from the star finder and chart viewer.

New features:

  • Lunar calculation and distances between two objects (more about this)
  • Student table printer - This is a daily table of Equation of time and declination for the Sun. It can be used to calculate the meridian passage with just one table (more about this)
  • Star Finder - The polar chart may be centered in a celestial sphere point. In older versions, the chart was always fixed to Earth position.
  • Star finder - Added a larger star catalog (Hipparcos 150) as an option to the default 56 navigation catalog.
  • Star finder - Added more color options.

Update is available for registered users of versions 4.0 and up (CD-ROM and electronic versions).
If you did not receive the update notification via e-mail, apply here

AUG/30/2004 - Navigator 4.5 released

Navigator 4.5 was released today (aug/30/2004) with many new and improved features. It includes new options, like dip short for land navigation, sextant calibration table, parallax for planets, more detailed refraction formula etc. The celnav module interface was revised and reorganized to reflect the celestial navigation workflow. I also added support for Windows XP visual themes.

This is also a service release. Several small bugs were fixed. I corrected a problem in the celestial engine, which affects some stars at early dates. Read more about the problem here. The upgrade is recommended to all users. Read more details about the release here.

All registered users of version 3.0 and up are entitled to free upgrade (download). Apply to upgrade here.
A CD-ROM upgrade is also available ( CDROM version users only. There is a US$10 shipping & handling charge ).


OCT/29/2003 - Navigator "in the box" released

Navigator software for Windows is now available as a packaged product. It includes the software CD-ROM and a 68 pages illustrated booklet, packaged in a compact DVD type plastic box. Very convenient to have on board. The product price is US$ 49.95.

The book includes a revised "celestial navigation fundamentals" text and program usage instructions. The software also received minor corrections and improvements and the version number increased to 4.2 (the online version will be upgraded soon)

The product is available online from Celestaire Inc. Click here to buy.


DEC/20/2002 - Yet another sextant: the CD-Sextant

A few months ago I published a do-it-yourself octant design (click here to visit). This project was a lot of fun, but a lot of work too. The results obtained from this instrument were quite good and proved that an inkject printer (at least my hp-810c) can be used to print a precision instrument scale.

But in the end I figured that it was too complicated to appeal to the average 21 century busy person. So I went back to the drawing board and designed the radically simple CD-Sextant, a sextant build over a CD. Its small, easy to build and requires only office tools.

Of course it has limited precision and is sometimes difficult to trim, but can be used as a 1st sextant. I think it can also be used in a number of science projects involving trigonometry or astronomy.

Click the link below to visit the CD-Sextant project:

Ok, ok. I promess I will put these silly toys away and get back to code writing :-(



OCT/07/2002 - The Navigator Store is on the air

Surfing on the Internet, I found this interesting company that sells, prints and delivers T-shirts, caps and a few other things directly to the clients. You can create your own store and upload the product designs. They take care of everything else. So I went on to open my own "hardware" store.

The materials and work are of good quality. I like the cap, which is very light and fresh.

The Navigator Store address is


New Navigator version

I've been busy this year, working on a large financial software project, and have not been able to put much time in the Navigator project. But now summer is coming here in the south hemisphere and I hear the call from high seas.

I'm working on the new version wish list, which I will be publishing soon. Among the ideas are:

  • Multiple LOP data entry grid. For productivity.
  • Printed celestial navigation reports.
  • Coriollis correction, for bubble sextants. Used in air navigation.
  • Dip short corrections. For lake navigation.
  • Parallax correction for planets. This usually small correction has been ignored in Navigator calculations... until now.
  • Calculation of angular distance between objects in the star finder. This is good to check the sextant and build a...
  • ..Sextant angle correction table. Not all sextants are perfect, but they can be improved if the error is predictable (and corrected).
  • Lunar calculation. Given 2 altitudes and a angular distance, calculates the time and longitude.

If you want to suggest any feature or improvement in Navigator software, it's just the right time. Just send me a message.


NOV/07/2001 - New articles on the subject of sextants

For long time I wanted to know more about Macromedia Flash technology for building Internet movies. After playing with the Flash 5 production software, I decided to do my first movie: a virtual sextant.

This is a pretty basic animation for those who never handled a sextant. It shows how it works and what are the components of this instrument, including arm movement, light rays and eyepiece view. This small movie is called the Interactive Sextant. It was also incorporated it to the celestial navigation fundamentals text.

Then I went on to complete another project I was planning for a long time: a homemade sextant. I took sometime to write a program to print the sextant scale using a ink jet printer. This was the missing part in my sextant design. After this, I was able to complete the instrument in one weekend, costing less then US$15 in materials. It took a little longer to document the construction process, which can be found in the X-tant project page.

Enough of sextants for some time...

OCT/4/2001 - Moon position calculations improved - Navigator 4.1 released

When one compared the official "Nautical Almanac" pages with the ones produced by the Navigator software for the same period, the larger difference was certainly in the Moon GHA. The Moon position is hard to predict because its orbit is very irregular. The Navigator Moon GHA error was up to 0.7'.

This was OK for LOP calculations, since it resulted in less than a mile error in the position (acceptable in celestial navigation). But was way too high to perform the lunar calculation. After some investigation, I was able to improve the algorithm and reduce this error to 0.2', which is within the precision of the best marine sextants.

On a more technical subject, I updated the UT to TD (Universal Time to Dynamic Time) difference table to include new precise predictions up to 2016 (with a good improvement over the previously used prediction formula, at least up to that date).

The Moon results are so closer that I'm releasing a minor version (4.1) with the new Moon calculations. I also updated the services "The Online Nautical Almanac" and "The Navigator Star Finder", freely available from this webserver (The shareware version 2.5 and DOS/HP 90LX version 1.3 have not been improved yet).

Another small change was the use of the label "IC" (Index error Correction) instead of the previous "IE" (Index Error). As a user pointed out well, this gives a better indication of the sextant index signal input convention.

A few users reported a problem in the sextant altitude input box. This problem is gone in this new version.

Navigator version 4.1 upgrade

Registered users of version 4.0 wishing to upgrade may ask via email (please inform registration email address and approximate date).

jul/04/2001 - Navigator 4.0 released

Navigator 4.0 is now available. This new version has many new and improved features.

Star Finder
The star finder was improved, particularly the printed results.
> Now the star chart and table are printed in a single sheet of paper.
> Boat course indication, for easy orientation.
> Improved celestial object identification in the chart . Now all planets have their own icons, for easy identification. The most visible stars (mag<3.0) are also indicated by a larger star icon.

Celestial Navigation
> Checkbox do select/deselect LOPs, for Astronomical Position calculation. Now you don't have to delete a LOP that is either wrong or nearly parallel with other LOP. Just deselect it and recalculate the position.
> Automatic LOP transport. In the prior versions, to calculate a running fix, it was necessary to transport each LOP by hand. In version 4.0, you can specify the boat course and speed; and the LOPs will be automatically transported ( either to current time, LOPs mean time or last LOP time ) when calculating the astronomical position. This feature makes calculating running fixes as easy as normal twilight positions.

Chart Navigation
> Implemented raster chart support. Now you can import popular GIF or JPG image formats (for example, a scan of a paper chart). You can use Mercator projections and even some satellite images. Prior to use, images have to be imported, using ChartMaker program, also included.
> Fixed chart viewer bumpy scrollbar behavior.
> Changed the help format from Windows .hlp to .html. The Help system was revised.

> Improved the GPS interface
> Full printer support for vector and raster images.



Users that have registered in the last 12 months are entitled to free upgrade to this version. Please contact the author via email for more information on upgrading. If possible, send approximate date of registration.


Navigator 4.0 screen shot


Other news:

dec/01/2000 - Navigator adopted by the Brazilian Navy School

I'm very happy to announce that the Navigator was adopted by the Brazilian Navy School (Escola Naval da Marinha do Brasil) for use in celestial navigation classes for junior officers. The school licensed 30 copies of the program.

During the review process, navy officers suggested several changes and clarifications in the Navigator, which were implemented and are now incorporated in version 4. As a result, the program is now much more usable - not only as a learning tool - but as a day-to-day navigation tool. I´d like to thank Captains Busnardo and Marcelo, for their help in Navigator development.

nov/2000 - Navigator web server now has accurate time keeping

Navigator web server ( have been running celestial navigation applications for some time.

One of these is the Navigator Star Finder

This application is supposed to present the user with the current GMT time, so he/she can view the current sky in any location, with accurate celestial position data for the most visible celestial objects.

But keeping the computer time was tricky. I would check it once and a while, but the suggested time was frequently off the mark.

That has changed. I´m now using the program Dimension 4 to synchronize the computer clock with a reliable time sources in the Internet. This program communicates periodicaly with these time servers and adjusts the computer clock, which is not very reliable in the long run, but performs well if adjusted frequently. Reference time sources include the U.S. Naval Observatory and several universities and research centers.

My server is now adjusted every 30 minutes. So the only time error expected is the server response latency, which is normaly below 5 seconds. I highly recommend the program Dimension 4 for computer time keeping. Check the programs web site.

ęCopr 92-2012
Omar F. Reis - All rights reserved