I am brand new working with VStar and unable to use "New star from AAVSO database". I can find some stars like Myra but "unable to obtain information for eps boo". I tried several other format ie Eps boo, EPS boo, eps Boo... nothing works. Could someone help with this beginner question?
Epsilon Boo is a binary star, not a variable (not an eclipsing binary) so it is not is VSX, and there are no observations of it in the AAVSO database. The format for the name you used (eps Boo) is correct. If you don't find any information when you try to load a star in VStar, check in VSX to see if it is there. If it is in VSX, look at the VSX record to see that it has an AUID. If it does not, you need to request one. If there is no AUID, it also means there are no observations in the AAVSO database.