In the US, astronomy and astrophysics are essentially synonymous. The words are interchangeable and don't indicate difference in coursework. Some schools may offer different tracks within their undergrad astronomy degree--one physics intensive track for grad-school bound types and one less physics intensive for those wanting to do say, K12 education or science outreach--but all graduate astronomy and astrophysics programs will have essentially the same course offerings. There may be some difference based on whether the astro department is independent (in which case you will take purely astro classes) or if astro is classified as a subfield in a university's physics department (in which case you might have to take some pure physics classes in addition to your astro classes, like quantum field theory or other less astro-y, more condensed matter/high energy things).
Also, it seems like you might be unaware that US graduate astronomy/astrophysics programs don't really do stand-alone masters degrees. There are very few schools I'm aware of that allow you to apply to just a masters. Instead, you are admitted to a PhD program and when you pass your exams, you are granted a masters and continue onward to the PhD without leaving. (Some people do choose to leave or "fail out" with a masters only, though). The system of just doing a masters then reapplying for a PhD is more commonly seen in Canada or Europe.