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Elective credits

In addition to compulsory elements, most degree programmes also have elective credits. These are credits you can earn in a variety of ways, for example by taking elective courses, studying abroad or doing a minor.

How many elective credits do I have?

The number of elective credits varies from programme to programme. Take a look at the programme-specific information in the Prospectus for exact details.


A minor is a cohesive set of courses that has been pre-approved by the university. A minor can allow you to explore subjects outside the boundaries of your own study programme. You can choose to follow a minor in Leiden or another university. There are special arrangements in place for Leiden students who would like to do a minor at Delft University of Technology or the Erasmus University Rotterdam. Read more about minors.

Elective courses

You can also choose to put together your own set of courses, selected from those offered by Leiden University or another institute of higher education. Make sure to request permission from your study programme’s Board of Examiners before doing so.

Going abroad

You can earn elective credits by studying or doing an internship abroad for a few months. Read more on our study abroad webpages or contact your international exchange coordinator or study adviser to find out about the options within your study programme.


Electives credits can also be earned through internships or research projects, either in the Netherlands or abroad. Ask your internship or research coordinator for more information. The Career Service can also assist you in looking for an internship place

Permission from the board of examiners

If you choose to follow a complete minor  in Leiden, Delft or Rotterdam you do not need to request advance permission. For all other ways of earning your elective credits you must always request permission from your programme’s board of examiners. More information can be found in the Prospectus or your study programme’s Course and Examination Regulations (OER).

Electives / Petition Requests in uSis

As well as the compulsory subjects, each degree programme offers plenty of opportunity for you to include your own electives. You compile your own study programme, together with your study adviser. Your elective components can be taken within your own department, but you can also do them in other departments, universities or abroad. in uSis there are a few options:

Study requirements and petitions

in uSis all courses that you plan to take for you bachelor or master study must be visible in your study requirement. Optional courses mostly are not part of the requirements, but must be inserted. The way to do this is by means of a petition request in advance. The Board of Examiners will set the petition request to the status Approved or External Education approved, which means that it is okay for you to follow these courses. You can find these status reports in you Student Service Center. If this procedure is followed, the course wil be visible in the study requirements after the result is inserted by the Science Student Administration.

Written permission

Often permission for a course is given to you by a letter. That would mean that the course stays in your study results and is not part of the actual study program in uSis. In that case a petition request is necessary. The handling of the petition request can in some cases be done by the Science Student Administration. Make sure the written permission, and a studyplan, both containing an official signature are handed in there. If you think this is applicable to your situation, please contact the Science Student Administration.

Petition request help

How you can submit a petition and more information on the variety of petitions is explained in the uSis-Help (check menu item Petitions). Below is more information on this subject. Important: You have to arrange the submission of a petition request well before you start the subject. If you fail to do this, you run the risk that this subject may not count towards your diploma.

The subject is already included under my academic requirements

Is a subject that you want to take already included under your academic requirements? Then this subject already has the approval of the Board of Examiners. You can therefore register for this subject (if it is on the timetable for the current year). Any grades already achieved will automatically appear under your academic requirements. You can ask someone within your department if a subject is going to be included in the current academic year.

Subjects within Leiden University

If you want to do a subject from another degree programme within Leiden University as one of your elective subjects, you will need a code for this – a so-called uSis course catalogue number. This is a 10-digit number. If it is a subject of the Faculty of Science, it starts with a 4 and ends in a Y.

In the e-Prospectus, the uSis course catalogue number for a subject is sometimes given. There is a summary of the course catalogue numbers for the degree programmes within the Faculty of Science under Sign up for Classes. If you are unable to find the course catalogue number for your chosen subject, then request it via usis-fwn@edufwn.leidenuniv.nl.

Thereafter you simply follow the procedure as described in the uSis manual. Once you have submitted a petition request, it is recommended that you keep your study adviser informed. The Board of Examiners will process your petition request. Once your petition request is approved, you will immediately be able to see it in uSis under your academic requirements. The applicable ECTS will be included once a pass grade has been input.

Subjects from another University

If you want to do a subject outside Leiden University, you can submit a petition request in just the same way, except that you choose the EXTERNAL COURSE petition request. There is also a full description in uSis-Help. Fill in as much information as you possibly can about the subject concerned and fill in the official name of the external organisation under 'external organisation'. When you have submitted an 'external subject' petition request, it won’t immediately be shown under your academic requirements. It will appear once the applicable grade has been entered. The Board of Examiners will consider the request and list it as 'in process' or 'external course approved'. After finishing the course, you hand in the grade to the Science Student Administration. Once it has been input, the subject will count as one of your requirements.

Courses that don’t count towards your exam programme (extracurricular courses)

On top of the ECTS needed for your exam programme it is possible to follow extra courses, for example courses from another programme or extra courses from your own programme. These courses are not registered as part of your exam programme (extracurricular = outside your curriculum) and will not influence your average grade, but they will be mentioned in your diploma supplement. To register these courses as extracurricular courses, you need to submit a petition request ‘Extracurricular course’ in uSis.


The first semester of the third year of the Astronomy bachelor's programme and of the double Astronomy/Physics bachelor's programme offers a total of 30 EC for an explorative minor programme or elective courses.


You may choose from various minors offered by Leiden University, Delft University of Technology and Erasmus University Rotterdam. Your elective programme is always compiled in agreement with the study advisor of the Astronomy bachelor's programme. Please note that deadlines apply to the enrolment for minor programmes. Visit the general page for minor programmes for more information.

Choosing a minor can influence your options for your Astronomy master's programme. Some Astronomy master's specialisations require certain mandatory courses that you may not follow when choosing a minor programme. More information about these mandatory courses for the various Astronomy master's specialisations can be found in the Course and Examination Regulations (OER) (in Dutch).

Core courses

Core courses within the Astronomy bachelor's programme are in the core package. This package consists of approximately 15 courses in astronomy, mathematics, physics and computer sciences. You may also choose from selected Astronomy master's courses. When choosing the core package, you will follow the mandatory Radiative Processes (6 EC) course and your own selection from the core package courses adding up to the remaining 24 EC. All electives need to be included in your Study Plan. An overview of all Astronomy bachelor's core courses on offer can be found in the e-Prospectus.

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