with two sailor bothers , who would know of the stars, constllations etc for navigational purposes, they might have shared their knowledge.

I'm sure she picked up a lot of information from them.....

I've just checked the sale notice disposing of all George Austen's effects after his death( inlcuding his library).(Go here for an old post on the sale)

Interestingly

A terrestial globe by Adams

is listed, together with a microscope.

Dudley Adams was a mathematical instrument maker and was appointed "Globe Maker to the King" in 1794.

Perhaps the celestial globe was given away to one of JA's brothers...these globes were usually in pairs .