Most bachelors offer an oppertunity to follow a minor during the third year. Depending on your major, this could be either 15 or 30 ECTS.
Being a coherent course package, minors can be used to orient yourself outside the boundaries of your own education. You are able to supplement your own education with knowledge, insight and skills, possibly from other disciplines, or deepen your knowledge of you major. A minor can also help you prepare for a master.
Listed below are the minors. Note that the minor "though Space and Time" is open for students from all faculties. The "Astronomy" and "Instrumentation and Informatics" minor are only open for students from the BSc. Astronomy or BSc. Physics.