How about replacing the walls with concealed sliding panels and using the wall cavity to house books?
I guess I'm used to having organised clutter, if I have something scribbled on a piece of paper I just know where in a pile of magazines and papers it is.
If you did dispose of them are your circumstances likely to change in the future and will it become a source of regret then? Are you likely to have the space for them?
A nice library is itself a thing of beauty even if you don't read and re-read every volume. I would suggest the rarer ones and larger sets you try to hang onto. A bunch of large cheap containers to line a garage wall floor to ceiling even. Cheaper more common books might be better suited as ebooks. I don't know if this is a possibility but what about asking a library if you can donate your collection on the proviso the books are kept together and you can reclaim any/all at a later date, particularly if you have many that they wouldn't have. That way you get good free housing for the collection and others will be able to make use of the books within the library. A university library might be willing to do something along these lines, perhaps even as a reference library in their astronomy rooms (if they have such). What about a local observatory you could loan the collection to? I think there may be options that don't involve you disposing of the collection permanently, and indefinite loan to some establishment/society is a possibility.