This is a quick look at NavPak Android & Kindle Edition with screen shots. This Beta is an initial release edition which includes Almanac, Sight Reduction, Plotting Sheet, Advance LOP, Great Circles, Star/Planet Finder, DR & TSD calculators, globe and maps. The Almanac in this copy is good till the end of August, 2017. The globe and maps are small scale for quick reference. The program also contains a Magnetic Variation map which is accurate until 2019.

Available free from the Google and Amazon App Stores.

Please read the DISCLAIMER below, before using for navigation.


When you start NavPak, the main menu is presented.


This initial release is a minimum tool kit of essentials for celestial navigation. Future releases will add more features.


Standard terminology, acronyms, abbreviations, and numerical formats are used through out the program, so that the experienced navigator can pick it up and start using it immediately.


A good way to start is to enter your Assumed Position and magnetic variation.


These are important for the navigator and casual star gazer. They are stored in the initialization file, along with the Destination and Dip.


NavPak gets GMT time from the computer clock, so be sure that your device is set to the correct time zone. To verify that NavPak is getting the correct GMT, go to the GMT Time panel in NavPak and press the button [Set to Clock]. This will show the GMT in the panel.




This is the Almanac Panel. From here, you can set the Assumed Position and time, then hit the [Calculate] button and it will calculate the GP of all the navigational stars (58), planets (5), Sun and Moon at the given time (GMT). For the Sun and the Moon, it will calculate the SD, and for the Moon, it will calculate the HP.


It also calculates the Altitude, and Azimuth of the body. This can be used to check your compass and as a star and planet identifier.


You can scroll through the list using the [Up] and [Down] buttons in this panel, or hit the [LIST] button and select the body of interest from the list (shown below).


The [T] button takes you to the top of the list. From there the [Up] arrow will lead to the Sun, Moon and planets, and the [Down] arrow will go through the list of stars.


If your Assumed Position is within a few hundred miles, that will work, but closer is better. If it is way off, then you will see it with excessive Intercepts, and when you do your plotting.


When you tap the number and decimal point keys, they will show in the scratch pad area above the panel. use the [Back Arrow] key to edit your entry as required. Enter the number in the scratch pad area and then hit a category key to enter the number in the panel.

In the example above, enter 45.67 on the key board, then hit the [Latitude Min] button to register it on the panel.


All the numbers you enter will be whole numbers, except minutes of arc and distance values which are decimals. Minutes of time are whole numbers.


Plotting Sheet Screen

This is a Mercator plotting sheet for your celestial sights. The white cross shows the average of the intersections of the LOPs, and the position of the cross is shown in the upper left corner of the screen. To fine tune your position, you can delete and add sights, and a new average is calculated each time. For example, LOP 5 should be thrown out because it is pulling the average to the North West.


Sight Manager Panel.


Use the Up and Down arrows to browse your sight list.


Yes No Dialog Panel.


This is a generic Question Panel which is used in various places in NavPak. In this case it is used to confirm if you want to delete a sight from the Sight Manager.


You can set your GMT from the phone's clock, or enter it in this panel. The button to set the clock makes it easy to mark the time of your sights.


If you are casually star gazing and you want to know the GHA and LHA of Aries, then you can get it with 3 taps on the screen. 1. Select [GMT Time] from the menu. 2. Hit the button [Set to Clock] then hit the [Aries] key, and there it is.


The LHA is based on the Assumed Position that you entered before.


This panel does the sight reduction.


The HS and Dip are entered here. The GHA, Dec, SD, and HP are carried over from the Almanac panel, or you can enter them here.


The Dip (height of eye) is stored in the initialization file.


The sight is also corrected for Atmospheric Refraction, based on the HS, and normal atmospheric conditions.


The Great Circle function uses your Assumed Position as the start point, and your Destination as the end point, which is entered in this panel.


The Assumed Position and your Destination are stored in the initialization file, and they are shown as flags on the Globe View.



You can set your magnetic variation in this panel.

The Map button leads to a world variation map.


This is the Sky View based on your Assumed Position. Shown here is the Free Axis mode. There are also preset views for Top View, North, South, East, and West views. Every time you tap on REFRESH, it calculates all the planetary positions and updates the model.


The Globe View shows the GP of the Sun, Moon, planets and stars.


This can be used as a tide predictor, lunch clock, and for Zenith Star Navigation without instruments.

The Globe View has 2 textures. Shown here is the NASA Blue Marble. The other texture is a NOAA map which is colored to show elevation and has a grid.


Star and Planet Identifier


This feature uses your HS and compass bearing to identify stars and planets.


The function searches the internal list of 5 planets and 58 stars. Also it gives you the SHA and Dec of the body to use with the Almanac.


Star List Panel 1


The Star List Panels are accessible from the Almanac Panel


When you select a body from the lists, it will go back to the Almanac Panel, showing the body.


Star List Panel 2


Deduced Reckoning


This function makes it easy to keep your Assumed Position updated, and can be used as a traditional Maneuvering Board. It is based on Great Circle formulas for accuracy at high latitudes.


Enter the estimated distance and direction traveled from your Assumed Position then hit the [CALC] button. To save the Relative Position as your new Assumed Position, hit the button [Save as AP].


Time, Speed, Distance Calculator


Enter 2 of 3 parameters (Time, Speed, Distance) then calculate the third.


Advance LOP


This is useful for a Running Fix and to check your time piece.

Always Under Construction.

Look for new items on the menu every now and then. New features will be published here first. Also available in the Amazon and Google AppStores. Please let us know if you have any questions or comments. Thanks for watching.

Quick Start Notes:
[ Click here for info ]

A simple excercise using NavPak Android:
[ Click here for example ]

Another excercise using NavPak Android:
[ Click here for example ]

Here is a glimpse into the life of a celestial navigator:
[ Click here for story ]

Assumed Position:
[ Click here for more info]

Planetary Positions:
[ Click here for more info]

Barometric Pressure and Temperature Corrections:
[ Click here for more info]

Meridian Passage:
[ Click here for details ]

Great Circles and Way Points:
[ Click here for more ]


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DISCLAIMER: In the ancient tradition of navigation, do not rely on a single aid to navigation. Before going offshore, you should have a hard copy of essential navigation materials. This program should be useful for celestial navigation, but this initial Beta release has not been extensively tested. A few dozen planetary positions were compared with the Air Almanac for 2016 and 2017, with good results.