Changes between Version 57 and Version 58 of AstroTechTalk
- Timestamp:
- 26 Jan 2015, 10:48:31 (9 years ago)
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AstroTechTalk
v57 v58 29 29 || '''23.01.2015''' || '''Peter Bizenberger''' ||'''Mission Impossible: The alignment of LINC-NIRVANA'''[[BR]] [[BR]]Patience and meditation is the way to reach Nirvana. That's what the Buddhism teaches. How is this related to LINC-NIRVANA? This instrument exists in principal just of three simple components: telescope, plus Adaptive Optics, plus infrared camera - all done before, easy - some people thought and also told! But, if one wants explore the full capability of a 23 meter telescope with this instrument, one has to invest a lot. The individual units are already demanding, but they are designed for the combination of the two 8.4 meter primary mirrors of the LBT (Large Binocular Telescope) and they have to be aligned with such precision accordingly. This brings existing technology to its limits - mission impossible? [[BR]] [[BR]]Peter Bizenberger explains the intricacy of LN and the requirements on the precision needed to align LN. A task which is done the first time at our institute in such complexity. To fulfill this task detailed planning and a large number of measurement technology and tools are unavoidable as well the control of the execution of each step are essential. Peter will present to us an overview of how the team handles the efforts from the design of the instrument to the fixing of the last screw, as well as of current the results. A thriller with lot of Action ....................................Items! [[BR]][[BR]]!Talk:German [[BR]][https://svn.mpia.de/trac/gulli/att/raw-attachment/wiki/WikiStart/2015-01-23_LN_alignment.pdf Slides: English][[BR]]Questions: German, English[[BR]]Answers: Swabian || 30 30 || '''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 || 31 || 06.02.2015 || Matthias Lezius[[BR]](Menlo Systems) || Technology and applications of frequency comb lasers||31 || '''06.02.2015''' || '''Matthias Lezius[[BR]](Menlo Systems)''' || '''Technology and applications of frequency comb lasers'''[[BR]][[BR]]The optical frequency comb is the core product of Menlo Systems GmbH. Since its invention it has triggered numerous applications in very demanding areas of science like e.g. ultra high resolution spectroscopy, calibration of (astronomical) spectrometers, precision ranging, optical clocks, ultra-pure micro-wave generation, frequency and time transfer. In a general sense it has become the swiss knife of precision metrology of time, frequency, and length. Even mass and gravitation have been reported to be measurable at increased precision using the frequency comb. In the present talk Matthias Lezius will present todays technologies how to build optical frequency combs based on femtosecond lasers, and how to apply this device to various metrological challenges. [[BR]][[BR]]Talk: German[[BR]]Slides: English[[BR]]Questions: German, English || 32 32 || 13.02.2015 || Martin Kuerster || Allocation of the MPIA integration halls in 2015 || 33 33 || 20.02.2015 || Ralf-Rainer Rohloff || Carbon fiber components in astronomical instruments ||
