# Star Pupil

> Celestial navigation practice aid showing all sight reduction steps. (iPhone/iPad app by Richard Craddock.)

- Source: https://appshunter.io/ios/app/star-pupil/id6463496579 (this page in markdown: same URL + `.md`)
- Developer: [Richard Craddock](https://appshunter.io/developer/1579756955)
- Category: Education, Utilities
- Price: Free
- Rating: 5.00/5 from 1 App Store ratings · 2 written reviews indexed
- Age rating: 4+
- Requires: iOS 13.0 · 15 MB
- Languages: English
- Released: 2023-09-06
- Data updated: 2026-06-06
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/star-pupil/id6463496579/reviews.md

## What is Star Pupil?

Star Pupil is a practice aid for learning Celestial Navigation. It does not merely produce the answers to sight reductions but rather shows all the steps along the way!

Traditional Celestial Navigation is straightforward and requires only a Nautical Almanac, Sight Reduction Tables, and basic arithmetic. However each step must be performed correctly, and small errors, like adding rather than subtracting, are easy to make.

Star Pupil sharpens your traditional Celestial Navigation skills by showing each calculation and each step along the way for performing a Sight Reduction and plotting a Line of Position.

Star Pupil shows all the calculations and steps for:
* Calculating Ha from Hs using a Nautical Almanac
* Performing a sight reduction for the Sun and Planets using Pub 229
* Performing a sight reduction for Stars using either Pub 229 or Pub 249
* Plotting LOPs for the Sun, Planets, and Stars
* Plotting multiple LOPs to get a fix

Additionally, Star Pupil shows the steps for finding twilight at your position, and looking up the best stars for taking sights using Publication 249 Volume 1.

## Key features

- Step-by-step sight reductions
- Plotting Lines of Position (LOPs)
- Calculations for Sun, Planets, Stars
- Uses Pub 229 and Pub 249
- Twilight calculations
- Star selection assistance

## Recent user reviews (2 of 2)

All indexed reviews: https://appshunter.io/ios/app/star-pupil/id6463496579/reviews.md

### 3/5 — Good concept but broken

*2024-03-13*

Good concept of an app to teach CelNav but unfortunately when I take several sights I can’t then proceed to doing the sight reductions. The app doesn’t do anything after that. I hope this can be fixed in a future update because I would find it useful.

### 5/5 — Great for practicing!

*2023-09-06*

This app actually helps you get better at doing sights reductions.

## Frequently asked questions about Star Pupil

### What is Star Pupil?

Star Pupil is a practice aid designed to help users learn and sharpen their celestial navigation skills. It provides detailed, step-by-step guidance for performing sight reductions and plotting lines of position.

### What celestial bodies can I calculate with Star Pupil?

Star Pupil allows you to perform sight reductions and plot lines of position for the Sun, planets, and stars. It also includes steps for finding twilight at your position.

### What publications does Star Pupil use?

The app utilizes standard nautical publications for its calculations, including Pub 229 for sight reductions of the Sun and Planets, and either Pub 229 or Pub 249 for stars. It also assists with looking up stars using Publication 249 Volume 1.

### How does Star Pupil help with learning?

Instead of just providing answers, Star Pupil breaks down each calculation and step in the sight reduction process. This detailed approach helps users understand the methodology and avoid common arithmetic errors.

### What devices is Star Pupil available on?

Star Pupil is available for iPhone, iPad, and iPod devices, making it accessible for users on the go.

### When was Star Pupil last updated?

The latest version of Star Pupil, 1.0.5, was released on September 11, 2023. The app was initially released on September 6, 2023.

### Is Star Pupil free to use?

Yes, Star Pupil is completely free to download and use. There are no in-app purchases or advertisements.

### What is the age rating for Star Pupil?

Star Pupil has an age rating of 4+, making it suitable for a wide range of users interested in learning celestial navigation.

## Version history (last 2 releases)

### 1.0.5 — 2023-09-11

Added the ability to specify the use of an artificial horizon for a sun sight.

### 1.0.4 — 2023-09-06

No release notes.

## More apps by Richard Craddock

- [Plan Your Sail](https://appshunter.io/ios/app/plan-your-sail/id1579756953)
- [NavCalc Dynamic](https://appshunter.io/ios/app/navcalc-dynamic/id1638841716)
- [ParaChord](https://appshunter.io/ios/app/parachord/id6449880245)

All apps by Richard Craddock: https://appshunter.io/developer/1579756955

## Related topics

[sextant](https://appshunter.io/ios/topics/sextant)

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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 2026-06-06.*