When applying for graduate study in Astronomy, is it more helpful to have a B.A. degree or a B.S. degree?
For graduate study in astronomy, it is generally more helpful to have the B.S. degree.  The main reason is that most graduate schools are looking for a strong physics and mathematics background, which gives the admissions committee a good indication that the student can handle the graduate coursework and will be able to be successful at research.

How can I find out whether classes I have taken at community colleges will be accepted at SDSU?
California has a web site that allows you to check on the transferability of your community college credits: www.assist.org. The web site has ample help pages to help you through the process. If you have questions about upper level undergraduate classes (which ASSIST doesn’t always include), feel free to contact us.

Can I get an astronomy degree at SDSU if I already have a Bachelors degree?
Only if you take courses through Open University. SDSU has hit enrollment limits and currently has a policy not to admit students that have a previous Bachelors degree. You can take up to 28 units of courses through Open University, so it is possible to complete a degree if you have satisfied almost all of your coursework elsewhere (like community colleges). See the Open University website for more details.

To take a class through Open University, you must have instructor approval. However, this will not generally be a problem because astronomy class sizes are usually small.