18 Aug 1999

Gamma-rays are the most energetic manifestation of light. They cannot be focussed by lenses or mirrors. To make an image with gamma-rays, it is necessary to use the coded mask technique. This method of observation is used by the three main telescopes aboard the Integral satellite. It is illustrated in one of the show cases at the Cosmorama.

The coded mask technique works by partially masking the opening of a telescope and measuring the shadow of the mask projected onto the detector. By knowing the orientation of the satellite in space and by analysing the data from the detector it is possible to determine the position and the intensity of the gamma-ray sources, and thus reproduce the image of the observed sky.

The model demonstrating the coded mask technique at the Cosmorama was designed by the staff of the Integral Science Data Centre (ISDC) in Versoix near Geneva, Switzerland. The ISDC is the data processing centre for the Integral satellite. It has the duty to analyse the observations transmitted by the spacecraft, to archive them and to distribute them to the worldwide astronomical community. An international staff of about 30 scientists and engineers works to fulfill these objectives.

Besides actual and future space missions, objects that have actually been in space play an important role at the Cosmorama, for instance a first generation Sputnik model. The exhibition "Living in Space" inspires visitors to wonder about living conditions in weightlessness. The reconstitution of a module of the International Space Station tries to make visitors feel physically how terrestrial norms become obsolete in space.

The Swiss Museum of Transport and Communication in Lucerne is open daily from 9:00 to 18:00.