NavList:

Hello Meg,

As an introduction, I am a professional Mariner and Sea Captain (aka Master Mariner).  I have been practicing Celestial Navigation (some Brits might call it Astro Navigation) for 21 years at sea. 

1) In addition to the hobbyists and yacht types, nearly every merchant deck officer in the world will have to have become proficient at Celnav.  While it many not be practiced daily onboard, all of them must be qualified to do it according to international convention (STCW).  In addition to this, many naval surface officers and ratings are also trained, but not to the level as the merchant officers.   As far as popularity, I would not call it popular.  There are few professionals who do it be cause we like it rather than we have to.

2) Celnav requires clear skies and a good horizon.  So sometimes it is not possible at all.  If the weather cooperates, the observer is trained, and the instruments are accurate; you can get a position of sufficient accuracy to make landfall where you want.  On a large ship, a profficient mariner can obtain fixes within 1 nautical mile of actual position.  On a small yacht, the accuracy is a bit less due to the motion of the vessel.

3) I agree with Brad's answer to this one.  I will only add that in todays world; Apps, computers, and calculators augment the traditional tabluar and slide rule methods of doing the math.  Basic sight taking techniques using accurate time pieces and sextants haven't changed much.

4) I think I answered this in #1

5) Brad is correct, very little

6) The knowledge in published media is very accurate, although some of the more esoteric aspects are harder to find.  There is always room for debate on various methods, but the core knowledge will get you a good position at sea.

7) There are various techniques depending on circumstances (land/sea/size of vessel) and personal style.  Generally you need an accurate time piece, a horizon (natural or artificial), one or more celestial bodies to observe (clear sky), a tool to measure the angle, and almanac data to locate the body in time.  Once you have those, you use the method of choice to turn the raw data into a usable position.

8) If there is any influence at all, it is insignificant.  Most modern style celestial navigators remain completely unaware of traditional Polynesian techniques for ocean sailing.  We don't even use the small amount of actual Celnav that Polynesian sailors use.  Our use of constellations is limited to identifying specific stars we want to use, typically during azimuth observation, and was developed independently. 

9) I have only general knowledge of Polynesian techniques.  As Brad mentioned, prevailing wind and waves play a big part, but they also use the rising and setting of certain stars and constellations to help them out.  As Brad mentioned, the wave information is very area specific and the stars work only in certain latitudes.  Western Celnav is far more universal and easier to learn.  The book I read on the subject spoke of how the younger generation of navigators from the islands were far more interested in learning to use a sextant than learning from the traditional navigator.

I hope that these answers help in your research project.  The NavList has some of the most knowledgeable people in the world on this subject, but I do have to say, that sometimes you can feel like Alice going down the rabbit hole on some of the threads.

B/Rgds,

Jeremy