HAVERFORD COLLEGE

DEPARTMENT OF ASTRONOMY

Astronomy 205a

Instructor: Professor Stephen Boughn, ext. 1146

Textbook: Astronomy: A Physical Perspective (2^nd Edition) by Marc L. Kutner. We will cover Parts I through IV (through Chapter 16) except for two chapters (7 and 8) on relativity. However, those two chapters should prove to be fun to read on your own. The remainder of the text will be covered in Astro 206b. Undoubtedly, this book will prove to be a valuable reference resource for those of you who choose to major in astronomy. Contrary to its "2^nd Edition" title, this is really a "new" book, and so we will invariably find a few typos and mistakes in the text. There is a website, http://www.astronomyaphysicalperspective.com/, at which you can find a current list of corrections.

Reference Material: Several other introductory astronomy and astrophysics texts will be placed on reserve in the Strawbridge Observatory Library and, of course, the library is filled with books on the subject. Don't hesitate to use them, especially if you find a particular section in your text hard to follow. Occasionally, readings from the reserve texts will be assigned.

Observatory Keys: In order to have access to the library and the telescopes after hours, it will be convenient for you to have a key to the Observatory. Take the signed Key Request Form to the Haverford Security office. They will tell you when your key will be ready. There is a nominal deposit that you will recover when you return the key. There is often a considerable time lag between turning in the application and receiving your key so deal with this right away.

Course Description: Astronomy 205a is the first half of a two-semester sequence (Astro 205a and Astro 206b) required for astronomy majors. The first semester is devoted to the study of stars, the premier residents of the universe, and our own Milky Way galaxy (referred to as the Galaxy with a capital G). An important component of the latter is the interstellar medium (ISM) that consists of everything that lies between the stars in the Galaxy. Although, it comprises only about 10% of the mass of the disk of the Milky Way, the ISM provides the material out of which new stars are born and is the recipient of the processed matter that stars shed during their lives. From the study of the ISM, it is possible to deduce a great deal about the history, including the formation, of the Galaxy. Together with Astro 206b (extragalactic astronomy, cosmology, and the solar system), this course will provide a broad introduction to astronomy and astrophysics and serves as a prerequisite for the study of advanced topics. About 2/3 of the course will be devoted to the study of stars and the remaining 1/3 to the ISM and Galaxy. Another goal of Astro 205a is to provide an introduction to observational astronomy. This goal will be addressed by completing three observing projects on the order of one every 4 weeks. These will require some additional instruction in the use of telescopes and cameras during the first few weeks of class (see below).

Assignments, Projects, and Exams: Written homework assignments will be due every two weeks. Collaboration on homework assignments is encouraged except on those problems where it is explicitly forbidden. Homework assignments are typically worth 30 to 40 points and a late penalty of 1 point per day (weekends excepted) will be assessed for late homeworks. Short, in-class quizzes on the reading assignments will be given every week. There will be two exams, one on stars and stellar astronomy and the other on star formation, the ISM, and the Galaxy. Written reports will be required for two of the observing projects. Course grades will be determined from performance on homework and quizzes (approx. 40%), exams (approx. 35%), and projects (approx. 25%).

Workshops: Several one-hour workshops on telescope use and on project reports will be scheduled during the semester.

Projects: Three observing projects will be assigned during the term. Written reports will be required for projects 2 and 3. The first project will begin the second week of class. Students will work in teams of three at the telescope. After being checked out on the telescope, students are allowed to sign up for independent use of the telescope as long as they are accompanied by another qualified observer. WARNING: The weather is a formidable foe. Even though the actual number of hours you spend observing will be few, you will have to be "on call" for much of the semester. You must be willing to give observing top priority on clear evenings. Otherwise, you won't be able to complete this part of the course.

I. Observing with the 12” Schmidt-Cassegrain Telescope: You will observe a variety of astronomical objects during the semester and submit a brief (one or two sentence) description of each of your observations.

II. Sun: A solar telescope will be used to measure solar limb darkening. An analysis of this data will enable you to deduce the temperature gradient at the surface (photosphere) of the sun. In addition, observations of the apparent movement of sunspots will be used to determine the sun’s rotation rate.

III. Stellar Photometry: B and V band photoelectric photometry will be used to measure the light curve of a Cepheid variable. An analysis of this data will enable you to estimate the luminosity of and the distance to the star.

Tentative Course Outline: