Since this is a fairly niche app, I don’t foresee a lot of specific uses outside of a person stargazing and wanting to know exactly which constellation or planet or other celestial object they are currently looking at. A way to add interest to this particular app(for reference, I’m using Startracker) would be to tap on a celestial object – a constellation, a planet, a star, etc. – and get information on said object. This could be a short summary of its significance, how it got its name, and maybe a link to its wikipedia page.
Expanding upon this application with a glasses-type solution would grow to encompass any possible information about the sky you could see in front of you. My first thought is a glasses app dedicated to bird watching. Birdwatching can be an extremely difficult hobby at times due to many different minutiae in bird species. Birdwatchers sometimes will record what they think a specific bird they saw is, and then have to research what they saw. For example, did you know that there are over 330 species of hummingbird? By using an on-board camera, an AR-glasses application could try and scan for whatever birds are in front of it and give the species name immediately.
In a roundabout way, an information-giving AR application could also send back information to help the population at large. An example could be something like a weather application. When a person is looking outside, the application will scan what the weather is like at that moment in time – cloud formation, if rain is falling, if lightning is seen, etc. – it will check against the forecast for a person’s area at that time and give them a precise measurement. The application will also send back the information scanned around the area, and allow weather tracking organizations to better analyze and predict what the weather is and will be like.