How the Hubble Space Telescope works

by Lisa Cardy

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THE Hubble Space Telescope's has given us out of this world pictures of dust storms on Mars, the birth of stars, galaxies, black holes and the edge of the Universe. But how exactly does this amazing telescope work

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��Press Association

The Hubble Telescope

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In 1975, the European Space Agency (ESA) and NASA began developing the space telescope. The Hubble Space Telescope (Hubble), named after American astronomer Edwin Hubble, took eight years to build, is 50 times more sensitive than ground-based telescopes, with�ten times better resolution. Hubble went into orbit in 1990.

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Hubble is a compound telescope. Light enters the telescope through the opening and is bounced off a primary mirror to a secondary mirror. The secondary mirror reflects the light through a hole in the centre of the primary mirror to a point behind it. Then smaller mirrors distribute the light to various scientific instruments. These various scientific instruments make Hubble the amazing astronomy tool that it is.

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The scientific instruments pick up the different wavelengths, or light spectrum of a celestial object that reveal its properties and features. Each instrument uses charge-coupled devices (CCD), rather than photographic film to capture the light. The light detected by the CCDs are digital signals. They are relayed to Earth and transformed into the amazing pictures that we see in the news and magazines.

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The various scientific instruments have been designed to cope with the conditions of space that may interfere with the telescope's ability to pick up images. The Near Infrared Camera and Multi-Object Spectrometer (NICMOS) pick up infra red light or heat from objects whose light is blocked by dust and gas.

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The Space Telescope Imaging Spectrograph (STIS) identifies an object's different colours. The specific colours tell us what elements are present in the object, and the intensity of each colour tells us how much of that element is present and so, what the object is made of. In addition to the chemical composition, the spectrum can tell us about the temperature and motion of a celestial object, depending on which end of the spectrum is represented.

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The HST is also able to zoom in on objects using the Faint Object Camera (FOC), a high resolution camera.

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So, now you know how Hubble works,�if there's any other piece of scientific equipment that baffles you, just click here to ask about it.