Preface - The mass of the black hole at the centre of the Milky Way

Astronomy is an accessible and visual science, making it ideal for educational purposes. Over the last few years the NASA/ESA Hubble Space Telescope and the ESO telescopes at the La Silla and Paranal Observatories in Chile have presented ever deeper and more spectacular views of the Universe. However, Hubble and the ESO telescopes have not just provided stunning new images, they are also invaluable tools for astronomers. The telescopes have excellent spatial/angular resolution (image sharpness) and allow astronomers to peer further out into the Universe than ever before and answer long-standing unsolved questions.
The analysis of such observations, while often highly sophisticated in detail, is at times sufficiently simple in principle to give secondary-level students the opportunity to repeat it for themselves.

This series of exercises has been produced by the European partner in the Hubble project, ESA (the European Space Agency), which has access to 15% of the observing time with Hubble, together with ESO (the European Southern Observatory).

Figure 1: The ESO Very Large Telescope
The ESO Very Large Telescope (VLT) at the Paranal Observatory (Atacama, Chile) is the world's largest and most advanced optical telescope. With its supreme optical resolution and unsurpassed surface area, the VLT produces very sharp images and can record light from the faintest and most remote objects in the Universe.