ASTR 255 / PHYS 295: This course serves as a foundation for the Astronomy & Physics majors . The class goal is to prepare students for professional research in astrophysics. The course will cover observational data reduction methods and comparison to theoretical models. See the class schedule for more details. Problem sets will be based on data from on-going astrophysics research programs at Yale. Prerequisites: A strong background in high-school math and physics is essential; some previous knowledge of astronomy is recommended. Experience with statistics and computer programming will be helpful, but is not required. The course is intended for Astronomy and Physics majors; interested non-majors are welcome with permission of the instructor. Textbook: The required text "Observing the Universe: A Guide to Observational Astronomy and Planetary Science" by A. J. Norton is available at the Yale Bookstore. This book covers most technical aspects of the course, except computer programming and the scientific problems themselves. The text will be supplemented by a variety of handouts and online resources. Computer Programming: The majority of astrophysical research is done on the computer. In this class, we will use the Python computing language. No prior Python experience is required. It is expected that students will have some familiarity with general programming, or be prepared to quickly learn the basics of computing.