Celestial Navigation

I use this for sextant practice, plugging in my readings and comparing them to my known location to improve my sighting technique. Quick, easy, and accurate. It hasn’t been updated in 5 years, which is troubling, but it is still working on iOS 26.3.

This app is really good. Everything you need, full service. Not hard to learn. Wish list: option for latitude longitude and time in decimal seconds. Verbose position output and confidence value.

From height this calculates a positive dip. I think that dip is always a subtraction from read on the sextant.

This app is terrific! It is good to learn the “long way” of plotting your position but once you learn, then this app makes it so much easier and faster. All you need is your sextant and your watch and let the fun begin.

You put your sextant reading and it will give you a line of position. No need for nautical almanacs. But it does show all the variable values so you can double check your own calcs.

This is a terrific app for reducing celestial navigation sights. Easy to use and is exceptionally accurate. You can change the settings to suit your preferences. It will store your sights and allow you to select which ones to plot. I’ve tested it many times against hand calculations and every time and it comes right on the money. I highly recommend this app.

There is evidently a lot of thought and effort that has gone into the math and the mechanics of this app. It definitely has potential to be great. Unfortunately user interface problems detract from its usefulness. One example. Depending the size of your screen, you might or might not be able to enter latitudes and longitudes. On my iPhone 7, the digits are obscured due to lack of space.

This app has everything that one needs to resolve several sights into a fix. Nothing is missing. There is no clutter of unnecessary “features”. The best app that I’ve seen for celestial navigation. The inputs are: * assumed position entered by user or taken from device's GPS chip * date and time entered by user or taken from device's GPS chip * celestial body selected by user from a list of sun, moon, planets and stars * altitude of the celestial body read from sextant entered by user (Hs) * index error, if any, entered by user The outputs are: * actual altitude of the celestial body (Ho) * calculated altitude of the celestial body body (Hc) * intercept distance and direction (towards/away) * azimuth (Zn) details of the calculation from sextant altitude to observed altitude are shown. details of calculation from assumed position longitude to LHA of body are shown. The calculated line of position can be saved to the "Records" and placed on the provided map via a single click. All calculated lines of position stored in the "Records" tab can be displayed or hidden from the map. This allows each set of sights to be viewed separately without having to delete the previous set of sights. A "Starfinder" uses the device's GPS and orientation to show each celestial body. NOTES: 1. By default, the stars are sorted by number...use "Options" -> "Settings" -> "Sort stars alphabetically" to sort by name rather than number. 2. By default, the time is set to local time rather than GMT/UTC.

I’m running this on an iPad 4 Mini and having a blast relearning what I once learned with a calculator and reams of graph paper. Seamless integration of sights, reduction, and plots. I especially appreciate the sight entry, storage, edit, and selection features — well thought out and very handy. Simple and capable, I will be using this for fun and to teach and demonstrate the craft. Thank you for the superb app!

A free app that is fully capable of calculating a line of position directly from a sight. Unfortunately after the first couple of sights the app won’t open anymore and just crashes immediately on startup.