This page contains a Flash digital edition of a book.
FEATURE EUROPEAN EXTREMELY LARGE TELESCOPE


What we are trying to do is to move forwards by thinking “how should we be carrying out this work on the big scale?”’ The new process developed for the prototype E-ELT segment by the team at the UK National Facility has taken a step in this direction. Manual intervention and handling of segments has been reduced, so there is more automation and less scope for damage. Walker explains: ‘With further development, which is underway at the moment, we believe the process chain that we have developed will end up as a faster process. This approach will ultimately have an effect on the optics industry.’ In the finished telescope, each segment will have a unique location where it must be held securely and without distortion so that the ensemble will function as a single giant


www.electrooptics.com | @electrooptics


ellipsoidal mirror. It is vital to control the form of the segment edges because edge-roll, the distortion of the optical surface in the region near the transition, degrades stray-light and IR-emissivity performance. The primary mirror will be made out of 798 segments, which are all 1.4m in size, corner to corner, and 50mm thick. One of the key goals for the E-ELT project is to identify extra-solar terrestrial planets, and a large aperture is a key parameter in getting the high resolution needed to achieve this. The individual mirror segments must be aligned so that the gaps between them are reduced to within a small fraction of a wavelength. If the segments are not correctly in phase, only the resolution equivalent to the aperture of a single one of the mirror segments would be achieved. ➤


One of the key goals for


the E-ELT project is to identify extra-solar terrestrial planets, and a large aperture is a key parameter in getting the high resolution needed


NOVEMBER 2013 l ELECTRO OPTICS 17


European Southern Observatories (ESO)


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40