https://www.google.co.uk/url?sa=t&source=web&rct=j&url=http://www.rmg.co.uk/explore/astronomy-and-time/time-facts/harrison&ved=0CIwBEBYwFmoVChMI17jbj4bNyAIVypwaCh24vQ78&usg=AFQjCNFgmvCW1TISR7EgCvalRxYwEHiuWw&sig2=LikTisV5UCB92Q05KQHcNg
Nah that would never happen.
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Other way round, I think. A practical method for longitude had to wait for the development of accurate clocks.
I recommend Dava Sobelâs excellent book Longitude for a very readable account of the search for a means of determining longitude and John Harrisonâs eventual triumph.
I wonder how much was technological optimism and how much was technological pessimism:
The case for it being driven by optimism is obvious; âWhy worry about the GPS going down? Nothing could threaten our satellite systems!â; but it wouldnât be entirely surprising if there are at least some(not all; but possibly a a list that overlaps unpleasantly with the ones we like) missions where if GPS and/or other high end imaging and navigation systems arenât available you might as well stay home.
If you were already sailing, youâd obviously want somebody who knows how to run away with a sextant; but anything small enough to be carrier launched is going to get substantially less useful if you canât depend on GPS and fancy imaging and target selection to guide the relatively small payload to the target a reasonable percentage of the time. In Vietnam, say, we didnât use groups of âbig bellyâ B-52s just because of an enthusiasm for overkill; but because when you are dropping unguided bombs at a target you arenât entirely sure of, from high enough to avoid the worst of the AA, 60,000lbs of ordinance just isnât enough.
Inertial guidance has presumably still improved, as have laser-designated and air-to-air guided munitions; but there would still be a variety of effects, largely bad, on the usefulness of the navy, even if they can get their ships exactly where they are supposed to go. That still wouldnât explain a lack of enthusiasm for having the ability to run away without crashing into anything; but it wouldnât be entirely surprising if there are some deeply pessimistic internal assessments of how poorly some of the intended roles of various navy assets would go in the absence of various other elements that would be unavailable.
Iâm surprised that rates of error in clocks are close enough to constant that you can do error compensation by such relatively simple means.
Are the devices that somebody doing reasonably serious navigation would call âchronometersâ nicer hardware(in the computing context, a quartz RTC is assumed; but the low bidder is also assumed, and temperature control is pretty much unheard of, temperature compensation is aâŚmaybeâŚfeature; some more demanding applications, like cellular base stations, get fully temperature controlled quartz or Rubidium oscillators; the ubiquity and low cost of GPS time means you donât see anything more stable outside of standards labs terribly often); or did the people who wrote the NTP clock discipline algorithm gleefully overcomplicate the problem because such is the spirit of engineering?
There are sextant apps, but I doubt their accuracy very much: you donât have a divided view like a sextant, so you have to take two pictures and rely on the accelerometer for angle while the vesselâs movement screws with your gravity normal. Then you can use a filter foil to take a picture of the sun, but stars with consumer grade cmos cameras can only be achieved with a very long shutter, which will again screw your accelerometer measurement.
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Phones have more sensors than accelerators. They also typically come with magnetometers (which can help with latitude, I guess. But also for just finding the offset of what orientation the phone originally was in) and vibration sensors for the optical stabilization of the camera. Those all are useful in this context in addition to the accelerator. Additionally, you could have a âstandard starâ made with a laserpointer bolted to the ship, which would be great for stabilizing the cameraâs view post-photo.
Thanks will look into that.
We all know who youâre talking about. 
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Automated star sensors have been used in space flight for decades, but space is a much more benign environment for astral navigation than the sea, as you donât have random movement influences nor atmospherical disturbance, and also you usually have a âdark sideâ you can turn to. Forget anything magnetism-based, thereâs too much metal on modern ships. Large ships use gyrocompasses, and even on a small yacht a deviation table has to be compiled. Any uncalibrated handheld compass is unsuitable for navigation. Vibration sensors could possibly be used to increase the accelerometer accuracy, but they suffer from the same chaotic influence of wave movement as the accelerometer. It would take an extraordinarily smart algorithm to compute the true inclination of any object out of that. So does anything projected from the ship, but that could maybe be stabilized. I donât think you can achieve any purposeful accuracy without special hardware. At the very least you would have to calibrate your camera to correct for the various types of distortion introduced by the optics, and smartphone optics are so tiny they are bound to have a lot of distortion. That said, when you have to calibrate your camera anyway, you could just as well put a wide-angle lense on it, so you can perhaps âshootâ your star and the horizon in one single picture; that would circumvent the whole angle issue. But again, at night you need a long exposure ruining the fix on the horizon, and by day you would need a filter on that part of the image that captures the sun, while the part with the horizon must be left unobstructed 
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Itâs not bad but very light on the technology for the typical boingboing reader.
A better bet might be this:
I canât really recommend the best book on the subject because it is very expensive, but this is a problem for all horological texts that donât have government resources behind them. A friend of my fatherâs published what was at the time the most authoritative book on Breguet - and barely broke even (by the time he died his collection was worth millions, though - he started collecting when clocks and watches were relatively cheap.)
I probably have the same name in mind: But is it fair to call it a âlargeâ company? âOverwhelming hugeâ seems to fit better.
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