There are a number of possible career paths in the field of astronomy. Since most professional positions in astronomy require graduate-level education, the Astronomy & Astrophysics undergraduate major at IU is designed to prepare students for graduate study leading to a Masters and/or Ph.D. degree. Most astronomy research is done at either universities or national facilities such as NASA centers (e.g. the Goddard Space Flight Center near Washington, DC) and the national and private observatories (e.g. the National Optical Astronomy Observatory in Tucson, Arizona or Carnegie Observatory in Pasadena, California). Astronomers at universities typically spilt their time between carrying out research projects and teaching at the undergraduate and graduate levels. In addition to these research positions, other careers in astronomy involve teaching at the college or high school level, and working at planetariums and science museums, and working in computer support positions for NASA contractors. Related careers that build on an astronomical background include scientific writing, various positions in the defense, surveillance, and environmental fields, and military work (particularly with the Air Force).