Back in the 1600s science was much less specialized. You didn’t really have biology, chemistry, physics, and even mathematics for that matter as fully separate disciplines. If you did science, you were a “natural philosopher” and that was that. Now even physics by itself could be argued to be about a half-dozen separate disciplines whose overlap is not always so large.
Astronomy is often considered to be a sub-discipline of physics depending on the context, and in fact many universities have a “Department of Physics and Astronomy”. My undergrad university does, my current university was only the “Department of Physics” until quite recently when we greatly expanded the number of astronomy faculty. In any case it’s convenient to have astronomers and earth-bound physicists in the same building since so frequently they’re dealing with the same problems – spectroscopy, high energy particle physics, plasma dynamics, you name it.
All of which is a roundabout way of saying “Holy cow, have you seen the pictures from the new Solar Dynamics Observatory?” They’re just astonishingly impressive.