NavList:

"I wonder if it is a US vs Rest of World thing?"

Well, yes! I thought I said that. Did you see my earlier posts on this topic??

To reiterate: before about 1920, the subject was called "nautical astronomy". That is, what we call today celestial navigation was known as nautical astronomy. After that, presumably because of the transition to aerial navigation, new names for the subject became popular. But this is culture. Different names became popular in different schools of navigation. It's not as if there was a law stating that navigators in the USA had to call it "celestial navigation". It was just popularity. That phrase stuck, it 'had legs', in the USA. Meanwhile, in most sectors of British navigation culture, the name "astro-navigation" caught on. Internationally, outside of the English language, the overwhelmingly common name is "astronomical navigation". But remember that all of this culture. It's driven by the same forces of popularity and style that drive musical tastes and other choices of colloquial lingo. There's no right or wrong. There's no law of language.

Whatever name you choose to describe this subject, your goal is simple: communicate, reach the maximum number of people among those who you intend you reach. And with that goal in mind for an English language audience, the best name of the game is "celestial navigation (also known as astro-navigation)". That is, use the standard American name with the slightly less popular, but certainly equally valid, name referenced parenthetically. With those words, you will communicate with the largest number of readers. 

Frank Reed