Which u.s. College is the best college in the u.s. For astronomy?
You should look for a school with professors that publish papers in the particular area of astronomy that you are most interested in. You can also look in "The Astrophysical Journal" and "Solar Physics", which are two highly respected astronomy journals; look there for names of people who publish in areas that interest you and find out where they are now or where they went to school. However, be aware that some institutions discourage their own undergraduates from entering their graduate program, so factor that possibility into your decision as well.
You can look at the following site; it has information on which colleges and universities have astronomy degrees: http://www.uscollegesearch.org/astronomy-colleges.html
go to collegeboard.com and they will tell you!