Ralf Vandebergh
Image taken:
Jun. 2, 2011
Subject: X-ray telescope ROSAT, the final views RÖntgen SATellite ROSAT (joint German, British and US) The satellite got my attention recently, after media messages that it would soon decay and possibly even not totally burn up. Possibly up to 30 individual debris items with a total mass of up to 1.6 tons might reach the surface of the Earth predicted for around November 2011. The X-ray optical system, with its mirrors and a mechanical support structure made of carbon-fibre reinforced composite – or at least a part of it – could be the heaviest single component to reach the ground. The attached image, taken exactly 21 years and one day after launch, might be one of the last images we see of this orbital X-ray observatory. The elongated brighter main body visible, must be the telescope, a four-fold nested Wolter I telescope with an 84-cm diameter aperture and 240-cm focal length. There are some weak details visible, especially some dark areas and one remarkable dark area apparently separating the bright beam in a short and a longer part. That dark separation is visible in the 2 comparing images, made of different frames during the pass some 4 seconds apart. Some signs of solar panels are also visible seen from a relative short angle with the plane. Original orbit of ROSAT was 585 and 565 kilometres but what is now left is around 330 km altitude (june 2011). Though even at that relative short distance (some 10 km lower then the ISS minimal orbit) it is a hard object due to its small size. See this picture for comparison with a human: http://rammb.cira.colostate.edu/dev/hillger/rosat_image.jpg This picture does not show the telescope well, which is moutned on the other side of the solar panels. To see an art impression of the orientation of the telescope relative to the Earth see this picture: http://www.dlr.de/dlr/en/Portaldata/1/Resources/bilder/missionen/rosat/scaled/rosat1_l.jpg E-MAIL LIST FOR HIGH-RES SATELLITE IMAGING of Ralf Vandebergh the Netherlands ralf.vandebergh@home.nl web: http://ralfvandebergh.startje.be/vieuw.php?qid=328303
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