# Celestial Navigation — user reviews

> 22 indexed App Store user reviews of Celestial Navigation by Dr. Harald Merkel, rated 4.20/5 from 15 ratings.

- Source: https://appshunter.io/ios/app/celestial-navigation/id1458513224/reviews
- App overview in markdown: https://appshunter.io/ios/app/celestial-navigation/id1458513224.md
- Rating breakdown: 5★ 10 · 4★ 1 · 3★ 2 · 2★ 1 · 1★ 1

## Newest reviews (5 of 22)

### 5/5 — Superb software

*2019-11-26, version 1.3*

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!

### 5/5 — A very nice app

*2019-08-15, version 1.3*

This is a very nice and useful app. I would recommend it to everyone who enjoys sailing.

### 5/5 — Offenbarung!

*2019-04-18, version 1.3*

Meine Therapeutin hatte unrecht, die App ist alles was ich im Leben brauche!

### 5/5 — Updates lead to 5 stars

*2019-04-06, version 1.1*

Within a day of asking for a few minor tweaks the update came through.   
Excellent app just hug better. 5 stars.

### 5/5 — Genau und einfach zu bedienen

*2019-04-04, version 1.0*

Braucht man in Zeiten von GPS noch Astro-Navigation? Kann man als Backup begründen, aber eigentlich macht’s einfach nur Spass, diese alte Art der Navigation zu lernen. Nach langem Rechnen an Bord wüsste man gerade als Anfänger gern, ob das Ergebnis stimmt. Dieses App hilft, in Sekundenschnelle ein Ergebnis mit allen Zwischenschritten zu überprüfen. Der Sternensucher (nicht neu, aber neu mit den Navigationssternen!) hilft dem Anfänger, die Sterne zu lernen. Insgesamt ein schönes, rundes App!

## Most critical reviews (10 lowest-rated)

### 1/5 — Starfinder stopped working

*2026-07-17, version 1.4*

Just looked it up today again and star finder is not showing any information.

### 2/5 — Capable but crashes on iPad

*2019-04-07, version 1.1*

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.

### 3/5 — Dip error

*2024-11-22, version 1.4*

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

### 3/5 — Some UI issues

*2022-04-24, version 1.4*

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.

### 3/5 — Modernes Tool ersetzt mühsame Rechenwege, leider nicht genau

*2021-12-01, version 1.4*

eigentlich ein schönes Programm , das große Erleichterung gen+ber dem Nachschlagen in den Ephemeriden und dem berechnen mit dem Taschenrechner ersetzt. 

Leider sind die Berichtigungsberechnungen für Kimm und Refraktion deutlich ungenauer als die Schalttafeln, so dass das Fehlerdreieck größer wird.

### 4/5 — Bug with iPad when using star finder .

*2023-07-18, version 1.4*

Great app but the star finder displays stars for a second then goes blank on my iPad .

### 4/5 — Great App !

*2023-03-14, version 1.4*

The app is great but I can’t find where to read my fix after my observation of the lower limb of the sun

### 5/5 — Great tool!

*2026-02-27, version 1.4*

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.

### 5/5 — Position calculation

*2025-06-26, version 1.4*

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.

### 5/5 — Appli géniale

*2024-08-30, version 1.4*

Hyper intuitive et simple. Une visée plus calcul en moins d’une minute. Toutes les droites sont mémorisées. On peut sélectionner celles que l’on va retenir en final. Le transport de droites se fait automatiquement. Il suffit de rentrer le cap et la vitesse (à partir du point arbitraire). Le rendu sur carte est super. Je l’utilise depuis des mois et ai comparé la précision par rapport à d’autres applis, y compris le calcul d’estime. Tout est exact. Un vrai jeu de descendre aussi une étoile, planète, ou la lune, le tout en ayant le téléphone dans sa poche. Le starfinder aide à confirmer l’emplacement des astres en mode automatique ou à l’heure et lieu que l’on souhaite. Le plus de cette appli : la rentrée des données sur une seule page, ce qui évite les erreurs. Un seul coup d’œil permet de confirmer les paramètres rentrés et déceler un éventuel oubli.

## Most praised reviews (7 highest-rated)

### 5/5 — Wow

*2024-08-08, version 1.4*

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.

### 5/5 — Perfect.

*2024-07-07, version 1.4*

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.

### 5/5 — Exceptionally Accurate and easy

*2024-03-13, version 1.4*

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.

### 5/5 — Einfach und sehr gut

*2023-09-29, version 1.4*

Bitte jetzt noch die Farben der Linien/Kreise etc. wählbar machen,
großes Danke wenn es möglich wär.

### 5/5 — Exactly what is needed…no less, no more

*2021-11-14, version 1.4*

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.

### 5/5 — Inexpensive

*2021-06-04, version 1.4*

This is the first CelNav non-free app I have tried. Seems good value for money, I reproduced some sightings from 2018 with success. Be careful with the Index error: to add to the Sextant Altitude a positive quantity you must enter a negative quantity for Index Error!

### 5/5 — Good for teaching yourself

*2020-05-17, version 1.3*

This app is fantastic if you’re trying to teach yourself celestial navigation with no help. It allows you to check your working and see where you have made mistakes if you’re trying to get good at using tables or a calculator. You can use it to make up sights for you to reduce when you can’t see any celestial bodies, or to practice reducing sights in different locations. The only problem I’ve found is if you convert E longitude into W longitude (>180°W) it crashes the app if you try to use the map function.

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-07.*