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Changes between Version 55 and Version 56 of AstroTechTalk


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Timestamp:
16 Jan 2015, 16:00:56 (9 years ago)
Author:
Ralph Hofferbert
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  • AstroTechTalk

    v55 v56  
    2424[[BR]]Please send proposals for talks via e-mail to: gaessler, hofferbert - or also available in room 021 or 211.
    2525
    26 ||'''Date''' ||'''Speaker                      ''' ||'''Topic''' ||
     26||'''Date''' ||'''Speaker                      ''' ||'''Topic''' ||
    2727|| 09.01.2015 ||-- || No talk (Christmas break) ||
    2828|| '''16.01.2015''' || '''Wolfgang Gaessler''' ||'''Sharper vision with ARGOS eyes''' [[BR]][[BR]]Argos - the all-seeing - was a primordial giant with hundred eyes in the Greek mythology. ARGOS the Advanced Rayleigh guided Ground layer adaptive Optics System for the LBT (Large Binocular Telescope) was named after this giant, because the system will also have a lot of eyes. Recently, the first of these eyes were taken into operation. Now, ARGOS is watching with "Argos-eyes" for LUCI. [[BR]][[BR]]One year after the first laser stars have been projected on sky, the "Loop" could be closed on one side of the LBT simultaneously on three guide stars. The performance of the system was better than expected. A factor two improvement in image quality was the goal, but reality exceeded this prediction. Nevertheless, the images look not that spectacular than of other Adaptive Optics Systems, because ARGOS does not goal on the diffraction limit but on increasing the slit throughput for spectroscopy in a large range of atmospheric conditions. [[BR]][[BR]]Wolfgang Gaessler will present the project and its current status. He will tell us which problems are solved and which still have to be solved. And we will learn when ARGOS will be ready and what one can do with it. But the question is: Will ARGOS have the same fate as Argos? In the Greek mythology, Zeus ordered Hermes to kill Argos to free Io. Hermes succeed. In the real world it also looks like that some Argeiphontes (slayer of Argos) start to gather! [[BR]][[BR]]!Talk:German [[BR]][https://svn.mpia.de/trac/gulli/att/raw-attachment/wiki/WikiStart/2015-01-16_ARGOS.pdf Slides: English][[BR]]Questions: German, English ||
    … …  
    3030|| '''30.01.2015''' || '''Peter Hartmann (Schott AG)''' ||'''ZERODUR®: Glass ceramic with ultra-low thermal expansion '''[[BR]][[BR]]Requirements on shape and dimensional stability of high tech components are continuously growing. Mirror shape profile must be kept constant within 10 nm, in microlithography silicon wafers must be positioned to 0.3 nm precision. Active temperature stabilization must be complemented by using materials which change their extension lowest possible with temperature variations.[[BR]][[BR]]Here the glass ceramic ZERODUR® takes a prominent position with more than 45 years of successful application. Even though being unchanged in its composition it was subject of significant progress nonetheless in the last ten years. The production process enables mirrors of 4 and 8 m size with extreme homogeneity of the coefficient of thermal expansion in the 10^-9^/K range. Tempering processes basing on a physical model allow keeping CTE within limit of +/- 7×10^-9^/K. Even matching relative expansion Delta l/l to given temperature profiles for example for observatories is possible down to 10×10^-9^. CTE minimization is also possible for the temperature range 70 to 250 K. Bubbles, inclusions and striae content is very low as well as residual bulk stress. New processing methods enable lightweight structures with almost 90% weight reduction. Better modelling and an increased data base for bending strength support application at higher mechanical loads.[[BR]][[BR]]A large number of earth-bound and space-based projects prove the high material quality and its reproducibility, which is a decisive precondition for extremely large telescopes.[[BR]][[BR]]Talk: German[[BR]]Slides: English[[BR]]Questions: German, English ||
    3131|| 06.02.2015 || Matthias Lezius[[BR]](Menlo Systems) || Technology and applications of frequency comb lasers ||
    32 || 13.02.2015 || [[BR]] || Still vacant ||
     32|| 13.02.2015 || Martin Kuerster || Allocation of the MPIA integration halls in 2015 ||
    3333|| 20.02.2015 || Ralf-Rainer Rohloff || Carbon fiber components in astronomical instruments ||
    3434|| 27.02.2015 || Sascha Douffet || Occupational safety at MPIA ||