Please be warned: I am not a a nuts-n-bolts advisor and I value independently minded students. My main job, as I see it, is to help you develop into a young stand-alone scholar, brain storm with you and provide resources and ensure that your mistakes or failures are bounded. [Mistakes and failures are a part of learning process].
Please be aware that astronomy faculty do not take graduate students directly. Prospective students apply through the official portal. A committee appointed by the Department Chair reviews the applications and selects the students. The students are expected to take a full load of courses during the first year (7 astronomy & 3 physics courses). Typically, students being a research project during the first year but much of the work is during the summer of the first year. Note that students have full freedom to work with any faculty during the first two years. During second year some students pursue a different research topic while some continue their first year project. Student working with advisor initiates a thesis project during third year. Our department strongly encourages students (and advisors) to finish the PhD in five years.