Star Pupil is designed as a practice aid, a companion app for learning Celestial Navigation. As such, 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.
Why and How to Learn Celestial Navigation
When one carries a GPS device in one’s pocket every hour of every day, does it really make sense to learn Celestial Navigation? In a word: No. It would be the rarest of circumstances that would bring that skill into real practical use. Perhaps a Navy shipman on a secret mission where all ship’s electronics are turned off. Or perhaps an unfortunate sailor making an ocean crossing and losing all electronics from being… hit by lightning? Actual examples of the necessary use of celestial navigation are less than abundant.
What’s more, using celestial navigation doesn’t fully make sense except when one finds oneself out in the ocean. For near-shore sailing, the accuracy of celestial navigation (you’re very good if you can find your position within 5 miles) pales next to the techniques of coastal navigation, e.g., taking simple fixes to known landmarks ashore or using your depth meter to identify which isobath contour you are crossing.
Nonetheless, learning to “navigate by the stars” is a delightful endeavor and one I would recommend for the sheer joy of it. But if you’re going to do it, it is my firm belief that you should do it right, and that means without the use of any electronic devices.
Wait, what’s that? No electronic devices? No apps?? Why, then, write an app for Celestial Navigation??
Using an app to help with the art of traditional celestial navigation may seem a bit awkward or even feel like cheating. After all, if you allow yourself the use of a smartphone, why not just look up your location using the smartphone’s GPS?
But Star Pupil is not an app for doing celestial navigation.
Star Pupil is an aid to practicing traditional celestial navigation, and effective practicing is essential to developing any new skill. Star Pupil can help improve your skills more quickly than you could with books or videos alone.
So, read books. Watch videos. Practice, practice, practice, and confirm your practice with Star Pupil. And when you’re ready, leave the smartphone behind. Carry your Nautical Almanac and sight reduction tables down to the dock, and set sail knowing that all you need is wind, water, a good ship, and a star to steer her by.
Availability
Star Pupil is available for iOS in the Apple Store and coming soon to Android.
How To
Read about How to use Star Pupil, get tips and tricks, and access the FAQ right here.
Attribution
Star Pupil is built with React Native. It uses various components and libraries from NPM which are listed in the Attribution section of the Settings screen.
The app uses APIs for Celestial Navigation from the US Navy.
Icons come from Flaticon.com. I diligently copied their attribution link, below, however I think it is probably wrong. I used an icon obtained by searching for “Celestial Navigation”. In fact, I used this very icon. The link below takes you to icons about “Crossroads”. In any case, they’re pretty good icons. Thanks!