I'm a professional mariner, and amateur pilot, and I can assure you that celestial navigation is still being taught at maritime colleges. Gues the maritime world is a couble of decades behind the aviation industry, especialy when it comes to education. (The whole human factors thing is just about catching on too, to get your masters licence you now need to do a 'bridge resource management' course).
From a large stable ship, with a sextant that hasn't been dropped too often, it is quite posible to get within 2NM of your true position if you manage to get 6 or 7 stars 'shot' in the twilight. Using the sun with 3 hours of DR between your LOPs is obviously a lot less precise.
I never had the chance to use an aviation sextant with an artificial horizon, but I would imagine the maritime model would be more accurate. With the big disadvantage that you have to wait for twilight to get a position using stars.
If you don't wan to use an electronic calculator or computer for your calculations, but don't have the patience to learn the old fashioned way you can use volume 1 of the 'Sight Reduction Tables for Air Navigation'. With some practice you can plan, shoot and calculate 7 stars in about 20 minutes (although when I was a cadet, my chief mate considered them cheating
).
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