Nickname for a friend

I need to figure out the Sindarin words for star-gazer or just star watcher. He is really into astronomy and it would be fun. Sadly he is not one for Tolkien's world. I have tried repeatedly to get him to read the books. But I think it would be fun and interesting to call him an elvish name like Gilthoniel (Star-kindler). Thanks.

I’d go with a straightforward compound like Gildir.

I don't know words. Does that mean astronomer, or star-gazer? Also that you for the help.

I formed it from gil “star” and the root √TIR “watch, look at, gaze at,” so the sense is “star-gazer.”

Thank you for the help(I meant to say that before). I do know pronunciation, Gildir would be G-ild-ear or gild-ear. Again thanks.