Information from the European Southern Observatory ESO Press Photos 13a-e/98 19 May 1998 For immediate release | |
VLT 8.2-m Mirror Ready for Coating With the VLT UT1 First Light just one week away, the ultimate activities that lead up to this important event have started at the Paranal Observatory. Following successful optical alignment tests, cf. ESO Press Release 05/98 , the 8.2-m primary mirror has been removed from the first Unit Telescope (UT1). It is now in the Mirror Maintenance Building (MMB) and is being prepared for coating with a thin, highly reflective aluminium layer. The giant coating plant (cf. ESO Press Photos 24a-e/97 ) has been thoroughly checked and test runs have shown that it is ready to receive the 22-tonnes Zerodur mirror. Several firings were performed during the past days that deposited a proper layer of aluminium on a test target. The specialists have now decided to do the real thing tomorrow, Wednesday, May 20. The procedure involves moving the big mirror from its cell unto the supports of the lower half of the vacuum vessel (coating tank). The mirror surface will be thoroughly cleaned to remove any dust and other impurities. The lower half of the tank will then be attached to the upper part in which the source of aluminium is placed. The process is based on high-rate magnetron sputtering under high vacuum (< 2. 10 -4 Pa). It is carried out while the mirror rotates in order to obtain a uniform and highly reflective layer of aluminium on the polished mirror surface. Following this operation, the mirror will again be placed in its cell and returned to the telescope. After careful optical re-alignment, expedited by the newly gained experience, the Test Camera will be activated. The first astronomical images will be obtained, marking the moment of First Light . The following electronic images illustrate the recent work. More information about the Very Large Telescope (VLT) project is available on the ESO Web.
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ESO Press Photo 13a/98
[JPEG: 166k] The cell with the 8.2-m mirror has been detached from the lower part of the telescope tube. (Photo obtained on May 17, 1998). | 
ESO Press Photo 13b/98
[JPEG: 167k] The mirror surface is covered to protect it during the transport. (Photo obtained on May 17, 1998). | | | | 
ESO Press Photo 13c/98
[JPEG: 161k] The transport moves between the telescope enclosures - nos. 1, 2 and 3 to the right, and no. 4 to the left. (Photo obtained on May 17, 1998). | 
ESO Press Photo 13d/98
[JPEG: 139k] The top half of the coating vessel with the magnetron installed. (Photo obtained on May 16, 1998). | | | | 
ESO Press Photo 13e/98
[JPEG: 150k] The lower half of the coating vessel with the supports on which the mirror will rest. A test target (the curved segment) is seen at the center. (Photo obtained on May 16, 1998). | | | |
This is the caption to ESO PR Photo 13a/98 [JPG, 166k] , ESO PR Photo 13b/98 [JPG, 167k] , ESO PR Photo 13c/98 [JPG, 161k] , ESO PR Photo 13d/98 [JPG, 139k] , ESO PR Photo 13e/98 [JPG, 150k]. They may be reproduced, if credit is given to the European Southern Observatory. © ESO Education & Public Relations Department
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How to obtain ESO Press Information ESO Press Information is made available on the World-Wide Web (URL: http://www.eso.org ). | 
