It is possible to enter an Astrophysics or Astronomy Ph.D. program directly after obtaining a B.S. in Physics, as many programs in the U.S. and Canada accept students with a general physics background. While a strong foundation in physics is crucial, candidates may not need extensive undergraduate coursework specifically in astronomy. Electives in astronomy can supplement a physics degree, but the emphasis remains on mastering core physics concepts such as quantum mechanics, classical mechanics, electromagnetism, and statistical mechanics. Some institutions may offer limited astronomy courses, which could raise concerns about preparedness; however, research experience in the field, while beneficial, is not a strict requirement. Additionally, pursuing a Ph.D. in a department that combines physics and astronomy may enhance employability, as a physics Ph.D. is often viewed more favorably by employers. Overall, a solid physics background is deemed sufficient for success in an astronomy-focused doctoral program.