Automated celestial navigation

[Pizzazz]

My understanding of traditional celestial navigation is that you use a sextant to measure the angle between the horizon and a specific star, take 2-3 fixes then feed these angles and the time into an app that calculates the position of the boat. Clearly, one can do the calculations by hand instead of using an app.

Would it be simpler to have an app on the phone that takes many pictures of the sky, not necessarily of the horizon but the camera pointing upwards, calculating the angles from the pictures (calibrated for focal distance, etc.), averages these angles and coming up with an approx. position? There are apps that allow you to measure the angle using the phones built in sensors but these are accurate within a degree only. I calculate that with a 12mp camera and a 60 degree field of view, one can calculate the angle within 2-3 min accuracy. If averaged over hundreds of pictures, this should give you accuracy comparable to a sextant, no?

For reference, the automated star trackers on missiles and spacecraft were accurate to sub arc seconds and that was fifty years ago. It should not be that hard to get accuracy within a couple of nautical miles today, no? And this will be just an app on the phone, no other hardware required.

SV Pizzazz

p.s. This is all assuming no GPS

[Benz]

You might need better optics than a phone's light-gathering lens, which is tiny. But if you're going to use a device that requires electricity, you might as well use a GPS, which will get you far better than "a couple nautical miles." It might be a fun app to play with, but I can't see it as really useful--far less useful than A) using the GPS, or B) doing your celestial all without 'lectronic gizmos.
Also, don't most phones still have to be within range of land-based towers? mine does. I think you can get some sort of expensive and fancy satellite wifi-hotspot for your phone, but if you can afford and power that, you might as well throw down for a GPS.

[StuM]

Originally Posted by Benz

Also, don't most phones still have to be within range of land-based towers? mine does.

Only iCrap


I use various Android device hundreds of miles from the nearest tower.

[SeanPatrick]

See Greg Rudzinki's posts on using a camera for CN over at NavList.

[belizesailor]

While that could be a technically interesting project, and I think very feasible, doesnt it defeat the purpose...I think of celestial as a non-electronic back up when the electronics are fried...make it electronic and there goes your back up. No?

[belizesailor]

Originally Posted by SeanPatrick

See Greg Rudzinki's posts on using a camera for CN over at NavList.

Interesting stuff. Just skimming it reveals that it is feasible to do CN photographically (with the right gear), but that the problem is technically complex.