Celestial Navigation Made Easy


Making Observations

Take a Sight

After selecting the object to sight from the main screen, the sight screen will be presented which shows the current time and expected altitude of the object. Both are updated on the second.

If your device has an internal compass, the object icon at the top of the screen will help you find the object in the sky.  Point your device until the icon of the object is centered in the “[  ]”, then look up by the current expected altitude and there it is!  Very helpful when finding stars. 

After taking your sight with the sextant, touch anywhere on the screen to stop the clock and mark the time.  The sliders will be positioned at the expected altitude to help minimize any changes to make.  Move the sliders (for big changes) or touch the “+” and “-” signs (to increment/decrement by one) until the displayed altitude matches the sextant reading.  Then press the “Enter Observation” button.

If you stopped the clock by mistake or just want to try again, press the “Restart Clock” button to continue.

After selecting the bodies to be observed, the ezSights application provides simple interfaces to enter, evaluate and edit the sights you make with your sextant.

Display Sights

After taking one or more sights, press the “Display” button on the bottom of the screen to show all sights for the object against the arc of the expected value at the current assumed position.

This screen will help you identify sights that are inconsistent with other sights taken.  You may want to exclude them from being used when finding your fix or delete them altogether (see below).

The screen is automatically scaled to allow the display of all observations for the object.

List Sights

Pressing the “List/Mode” button from any other observation screen will take you to a list of all observations for the object.  There are 4 list modes available in this screen that are toggled by pressing the “List/Mode” button while the screen is displayed.

Select/Deselect Values

In this mode, a checkmark is displayed by each sight.  Touching the sight will remove or replace the checkmark.  Sights that are not checked will be displayed in grey on the display screen and will not be used when finding a fix.

Add or Delete Observation

In this mode, the standard iOS add/delete interface will be displayed and a now observation can be manually added or deleted.

Edit Observation

In this mode, touching the observation will display a screen that allows the observation to be edited.  Correction values for the observation can also be edited.

Show Sight Reduction

In this mode, touching the observation will show the sight reduction data for the sight (see below).

Sight Reduction

The Sight Reduction data for the observation shows the Nautical Almanac values for the exact time the sight was taken as well as the azimuth and all corrections used to arrive at an intercept value.

Directly Add or Edit an Observation

Editing Observation Values

If an observation has been entered and you find you made a mistake, that observation may be edited.  Similarly, the corrections for an observation may also be edited.

Starting in release 1.1.4 correction data is saved on a per-observation basis.  This means that you can specify different correction values in cases such as a dip short sight using different shorelines at different distances, using different limbs on the sun and moon, or taking sights at different times with different temperature or pressure values.

Directly Adding and Observation

If the “+” button is pressed while in the Add/Delete mode, a new observation will be created that can be directly entered.

Setting the date when adding or editing an observation is an easy way to go to a specific date without having to scroll through the selector on the Time/Date screen.  The application date value will be updated to this date and used for all further observations.