Astronomy today is a large, fast-moving enterprise, in which new instruments and theories are constantly evolving. We live in a golden age of science, and astronomy is enjoying more than its share of breakthroughs. As an astronomy major, you will come to understand how much of this works, and you will have opportunities to make your own contribution to humankind's understanding of the cosmos.
The astronomy major is under the umbrella of the Department of Physics and Astronomy. Until recently, a separated major wasn't available. You may wonder, then, what astronomy is, and how it relates to the other subject in the department, physics.
Astronomy is among the oldest of sciences. In the Renaissance the clean, mathematically predictable motions of the planets played a decisive role in the birth of physics. Physics and astronomy became even more closely joined as discoveries in atomic physics opened the path to understanding the true nature of the stars, and the development of nuclear physics finally made it possible to understand how they shine for so long. Over the past twenty years or so it has become clear that astronomical observations may be the only way to get at certain very big questions in fundamental physics, since the conditions of the Big Bang may never be replicated.
Even though astronomy and physics are intimately co-mingled, they are not quite the same. The fundamental aim of physics is to uncover the fundamental laws of Nature, and to apply these rules in situations where they are helpful. Astronomy, in contrast, is concerned with a particular object which we find -- the Universe -- and everything in it, in much the same way that geology is concerned with a particular object, in that case the earth. There is a discipline of geophysics, just as there's a discipline of astrophysics, but in geophysics and astrophysics, the physics is often not an end in itself, but rather a tool used to understand what is there. Physics is used in the design of instruments, the interpretation of the data the instruments produce, and finally in the construction of the grand theories which explain the evolution of stars, galaxies, and the universe (or the earth!).
Other disciplines come into play as well. Computers are used at every step of the way, not just to simulate physical situations, but to deal with the reams of data modern instruments produce. Some astronomers specialize in telescope and instrument building, and become very good engineers. Even chemistry has its place in understanding molecular clouds in space, cool stellar atmospheres, and the composition of planets. And because randomness is everywhere, both in the sky and in our data, some astronomers make very clever use of statistics. Astronomy is not a mere subfield of physics, but a truly interdisciplinary quest to understand the universe.