FINITO is the first generation VLTI fringe sensor, optimised for three beam observations, recently installed at Paranal and currently used for VLTI optimisation. The PRIMA FSU is the second generation, optimised for astrometry in dualfeed mode, currently in construction. We discuss the constraints of fringe tracking at VLTI, the basic functions required for stabilised interferometric observations, and their different implementation in the two instruments, with remarks on the most critical technical aspects. We provide an estimate of the expected performance and describe some of their possible observing and calibration modes, with reference to the current scientific combiners.
In this paper, we present an approach to generate optimal processing sequences of lots at cluster tools. We consider the problem of sequencing n lots, where each lot can be processed by any of m available cluster tools. The proposed method combines simulation and a genetic algorithm to generate lot processing sequences. We show that our approach leads to a significant reduction of cycle times at cluster tools.
We report in this paper on the design and progress of the ESO Laser Guide Star Facility. The project will create a user facility embedded in UT4, to produce in the Earth's Mesosphere Laser Guide Stars, which extend the sky coverage of Adaptive Optics systems on the VLT UT4 telescope. Embedded into the project are provisions for multiple LGS to cope with second generation MCAO instruments.The LGSF is designed, assembled and installed by ESO in collaboration with the MPE and Max-Planck Institut für Astronomie (MPIA) in Heidelberg. MPE/MPIA are responsible for the laser system, PARSEC (Paranal Artificial Reference Source for Extended Coverage), and for the LIDAR operation mode of the LGSF. ESO is responsible for the laser room, the laser beam relay, the laser beam launch telescope with servos, and all the diagnostic and safety measures. The LGSF becomes part of, and it is governed by, the UT4 Telescope Control System. LGSF has to adopt the VLT standards and to be retrofitted on the existing UT4 telescope.The LGSF has to be upgradable to produce and control 5 Laser Guide Stars for MCAO, in 2006. The current LGSF design already embeds provisions for this upgrade.In the design of the LGSF we take advantage of the field experience matured with the MPE/MPIA ALFA system, in Calar Alto. All design areas benefit from the ALFA experience, and the LGSF becomes truly a second generation Laser Guide Star Facility. The project was kicked-off in September 2000, and has reached the Preliminary Design Review milestone on April 2 nd , 2001. At this time we are progressing toward the Final Design Review. We report on the current design solutions and tradeoffs. * send offprints requests to: dbonacci@eso.org Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/14/2015 Terms of Use: http://spiedl.org/terms Proc. SPIE Vol. 4494 277 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/14/2015 Terms of Use: http://spiedl.org/terms
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