#Celestial navigation app full#
#Celestial navigation app free#

With this type of sight reduction we do not use an assumed position, but do all reductions from a common DR position, given at the top of the page.

The actual sight reduction at the time was done with an early version of the HP-41 nav calculator that we added a few of our own functions to. The actual 1982 navigation logbook page of the log 2614 sight session showing analysis done at the time is below.ДЇirst some background notes. The plots included are just intended to show what the layout of the DR track would look like-although the plotting is accurate, once the choices were made.) In short, just one sight of each body was selected, so it had no benefit at all of the others taken. The sights used for the sample plots (such as the one above) were selected almost randomly from the sights taken, with the hopes that the readers strive to improve the choices and overall navigation. That process is left as an exercise in the book, with detailed instructions and many examples.

Each body, as seen below, had several sights, and it is the task of the navigator to analyze these to come up with the best representative of the full set. (In the book HBS, the fixes along the DR track as shown above were not made from the optimum choice of sights.

This type of extra work is not often required in mid ocean, but could be valuable on approaches. This process can be helpful when sights are limited or in question, and it is the only fair way to evaluate what we can and cannot achieve with cel nav. Most star sights were pretty good, so this was not an issue at the time, but now we want to concentrate on doing best possible analysis of a single sight session. In the actual voyage we just took a center value of the intersecting LOPs as the fix. And indeed-in light of the present topic-we do not have this fix plotted in the best possible position. We are looking into Jupiter-Vega-Altair fix at Log 2614. Here is a picture of how that fix might show up on a plotting sheet of the DR track. When you have nothing but cel nav to go by, it is important to do the best you can with each sight, and to maintain good logbook procedures. It is set up as an exercise in ocean navigation that is intended to be used as a training tool to master skills in cel nav and ocean navigation in general. There are many sight sessions in the book all are analyzed in detail. The lack of electronic navigation was not a choice willfully made there simply were no options at the time, which in light of how far we have come, was not that long ago. No electronics at all except RDF, and that did not work well. It was in July 1982, Victoria, BC to Maui, HI. We are analyzing a sight session from the book Hawaii by Sextant (HBS), which is a record of the last voyage I did by pure cel nav.

We go over this process here and present a free Windows app forВ computing MLP along with a work form for solving for it manually. This note is background for another article to be posted shortly by Richard Rice and me entitled 'Most Likely Position (MLP) from Three LOPs.' We use the sights below as one example in that article, but do not include these details that must precede an optimized cel nav fix.

#Celestial navigation app full#

#Celestial navigation app free#