nl en

Astronomy Lab and Observing Project


Admission requirements

Knowledge of calculus and basic astronomical concepts. In terms of the Leiden curriculum: Praktische Sterrenkunde: basic error analysis, basic photometry & data reduction, 2-parameter linear chi^2 Inleiding Astrofysica: coordinate systems, magnitudes, basic stellar properties, HR diagram Programmeermethoden NA: basic knowledge of Python Modern Astronomical Research and Communication: Finding and reading research articles


In the Astronomy Lab and Observing Project you will learn how to prepare and analyse astronomical observations with a professional telescope

The scientific question will be conceived by you working in a group and will teach you how to work as a scientist.

The course consists of three parts. Each part is introduced in one or more lectures and carried out with the supervision of assistants during practical classes using computers running Linux. The first part introduces the students to photometry of stellar sources using both synthetic and aperture photometry with special attention paid to practical error analysis. The second part focuses on the fitting of models to observational data while the third part which runs parallel throughout the whole course, focuses on the definition and analysis of observations with the 2.5m Isaac Newton Telescope (INT) on La Palma and is carried out in groups of 3-6 students.

The course is defined by two substantial problem sets covering part 1 and part 2, while the observing project provides substantial freedom to the students.

The following themes are covered:

  • Telescope proposals, technical and scientific justifications.

  • Astronomical software (review) – ds9, topcat and python

  • Synthetic photometry

  • Matching of black body models to photometry

  • Aperture photometry

  • Error analysis for CCD photometry

  • Radial velocity modelling for exo-planets

  • Weighted chi square fitting

  • Statistical testing (type I and type II errors)

  • The chi square test

  • Markov Chain Monte Carlo

  • Scientific report writing

Course objectives

At the end of this course you will know how to prepare your own astronomical observations with a professional telescope and evaluate the results thereof.

After this course, you are able to:

  • Prepare and present in writing a science case for astronomical observations on a topic chosen by the group.

  • Design astronomical observations with a professional telescope.

  • Analyse and present the results of the astronomical observations.

  • Apply the techniques of synthetic photometry to spectra of celestial objects.

  • Analyse images of stellar sources and carry out aperture photometry on this, including practical error analysis.

  • Combine the knowledge of synthetic photometry with aperture photometry to analyse the energy distribution of stellar sources.

  • Formulate a model for planetary motion and fit this to observational data including observational uncertainties.

  • Apply Markov-Chain Monte Carlo techniques to observational data and analyse the results thereof.

At the end of the course you will have been trained in the following behaviour-oriented skills:

  • Abstract thinking

  • Evaluate the scientific proposals of other groups

  • Ability to construct and analyse a scientific case in a group

  • Correctly explaining and analysing complex and non-intuitive concepts

  • Ability to present results clearly in writing both in the form of reports and a poster


See Schedules bachelor Astronomy

You will find the timetables for all courses and degree programmes of Leiden University in the tool MyTimetable (login). Any teaching activities that you have sucessfully registered for in MyStudyMap will automatically be displayed in MyTimeTable. Any timetables that you add manually, will be saved and automatically displayed the next time you sign in.

MyTimetable allows you to integrate your timetable with your calendar apps such as Outlook, Google Calendar, Apple Calendar and other calendar apps on your smartphone. Any timetable changes will be automatically synced with your calendar. If you wish, you can also receive an email notification of the change. You can turn notifications on in ‘Settings’ (after login).

For more information, watch the video or go the the 'help-page' in MyTimetable. Please note: Joint Degree students Leiden/Delft have to merge their two different

Mode of instruction

  • Lectures

  • Exercise classes

Assessment method

  • Written report

  • Poster presentation

The course is divided in three parts that count equally. The first two parts of the course are done on the basis of an obligatory report and the observing project is evaluated on the basis of the quality of the observing proposal, the preparation and execution of observations at the telescope and the final presentation of results in the form of a poster. The final grade is the average of the grade of the three sub-components to the course.

Reading list

There is no textbook associated with the course. The necessary background material will be made available during the course.


From the academic year 2022-2023 on every student has to register for courses with the new enrollment tool MyStudyMap. There are two registration periods per year: registration for the fall semester opens in July and registration for the spring semester opens in December. Please see this page for more information.

Please note that it is compulsory to both preregister and confirm your participation for every exam and retake. Not being registered for a course means that you are not allowed to participate in the final exam of the course. Confirming your exam participation is possible until ten days before the exam.
Extensive FAQ's on MyStudymap can be found here.


Lecturer: Dr. R.J. (Reinout) van Weeren
Assistants: Sam de Regt, Nashanty Brunken, Stefan van der Jagt, Rick Dullaart, Martje Slob, Nelleke Theijssen, Quincy Bosschaart, Rosa Hoogenboom