Background Information

This activity is based on the principles of Inquiry Based Science Education (or IBSE) where students are encouraged to find their own way through an activity in a less-structured way than they may be used to in school lessons. A simple example of an IBSE activity is provided. Some of the elements of this particular IBSE activity, and astronomy in general, tie in with topics in the various curricula on offer in the United Kingdom. 

Navigating Your Way Through

On any page, there are links which may take you to extra information about the subject. You are encouraged to follow as many of these as you like. Links to material outside of this activity will usually open a separate window within your browser. At the bottom of each page in bold font, we highlight up to three or four places we think you might want to go to next but the choice is up to you - these are in no particular order and there is no right or wrong answer here. These will usually duplicate links that are within the text of that page.

Of course, you can always use the 'back' button on your browser or close a window that you no longer need. There is also a sidebar on the left hand side of the page which shows the various topics and groups them into subjects - again, this is not a suggested route for you, simply a way of seeing what other material is available.

Getting Results

There is no set time limit for this activity, but it may take around 6 - 8 hours to complete the material and reduce one dataset. When you have done this, we'd be really grateful to get your opinion on what worked and what didn't so there's a short survey on the Conclusions page. We also invite you to send us any results or reports that you produce.

A Rough Guide

While this activity is designed to allow students to explore different aspects to different levels at their own time, there are certain activities which need to be performed in approximately the following order ...

  1. Read through background material on star types in general and open clusters in particular.
  2. Understand what can be derived from photometry, especially in relation to open clusters and colour magnitude diagrams (CMDs).
  3. Download the software package Makali'i and some data from the Faulkes Telescope website.
  4. Analyse your data using a spreadsheet package such as Excel or Libre Office Calc and plot your results.
  5. Compare your results with existing CMDs and those produced by other students.
  6. Make conclusions based on your data and reflect on which aspects of this activity you enjoyed most. This allows us to suggest other activities you may like to try next.

Some of the terms in this activity may not be that familiar to you so a glossary is provided.

If you have any questions or comments on this activity, please send an e-mail to clusters (at)

Go to the first page to learn more about stars.

Find out more about IBSE.

An example IBSE activity.