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At Paranal Observatory in the YEPUN (UT4) telescope, two instruments are installed and equipped with adaptive optics systems: an infrared spectro imager (CONICA) below the adaptive optics module NAOS; and an integral field spectrograph (SINFONI). In the same telescope, the Laser Guide Star Facility (LGSF) is installed to provide a reference star to the adaptive optics systems. The LGSF is tuned to the sodium D2 line to use the resonance fluorescence of atomic sodium in the mesospheric layer at an altitude of 90 Km. The LGSF system has been fully operational for several years now. During this time, important modifications have been made to the system to increase its availability, simplify its remote operation and improve its performance. In this contribution, we report on the latest upgrades in hardware as well as the software of the system. Some upgrades like the exchange of the cooling system of the VERDI lasers, as well as the exchange of motors in the PARSEC laser system, have been critical to improve the performance of the system. We also describe the improvements in the maintenance and operation procedures and operational constraints we have faced so far. Finally, we present and analyze the latest technical performance achieved by the LGSF in operational conditions.

This presentation provides interesting miscellaneous information regarding the instrumentation activities at Paranal Observatory. It introduces the suite of 23 instruments and auxiliary systems that are under the responsibility of the Paranal Instrumentation group, information on the type of instruments, their usage and downtime statistics. The data is based on comprehensive data recorded in the Paranal Night Log System and the Paranal Problem Reporting System whose principles are explained as well. The work organization of the 15 team members around the high number of instruments is laid out, which includes: - Maintaining older instruments with obsolete components - Receiving new instruments and supporting their integration and commissioning - Contributing to future instruments in their developing phase. The assignments of the Instrumentation staff to the actual instruments as well as auxiliary equipment (Laser Guide Star Facility, Mask Manufacturing Unit, Cloud Observation Tool) are explained with respect to responsibility and scheduling issues. The essential activities regarding hardware & software are presented, as well as the technical and organizational developments within the group towards its present and future challenges.

The Laser Guide Star Facility (LGSF) is installed on the UT4 (Yepun) telescope at Paranal Observatory in Chile. On the same telescope, two instruments are equipped with adaptive optics: an infrared spectro imager (CONICA) below the adaptive optics module NAOS; and an integral field spectrograph (SINFONI). The LGSF is tuned to the sodium D2 line to generate an artificial reference star, for both CONICA and SINFONI. Although the LGSF is a complex laser system, rather different from the other instruments at Paranal, it has been designed to run remotely without any hand-on tuning for a period of one week. The LGSF system has now been in operation for several months, in conjunction with the Aircraft camera Avoidance System (AAS). In this article, we report on the technical performance achieved by the LGSF in operational conditions. We also provide a summary of the technical problems and operational constraints we have faced so far. We present the current operations and maintenance procedures implemented at Paranal. We also present the evolution of the human resources needed to operate and maintain the LGSF operational from commissioning to routine operations. Finally, we discuss possible improvements to reduce the workload to maintain and operate the LGSF.

The European Southern Observatory (ESO) operates its Very Large Telescope (VLT) on Cerro Paranal (Chile) with to date 11 scientific instruments including two interferometric instruments and their numerous auxiliary systems at 4 Unit Telescopes (UTs) and 3 Auxiliary Telescopes (ATs). The rigorous application of preventive and corrective maintenance procedures and a close monitoring of the instruments' engineering data streams are the key ingredient towards the minimization of the technical downtime of the instruments. The extensive use of standardized hardware and software components and their strict configuration control is considered crucial to efficiently manage the large number of systems with the limited human and technical resources available. A close collaboration between the instrument engineers, the instrument scientists in instrument operation teams (IOTs) turns out to be vital to maintain and to the performance of the instrumentation suite. In this paper, the necessary tools, workflows, and organizational structures to achieve these objectives are presented.

Two teams of scientists and engineers at Max Planck Institut fuer Extraterrestrische Physik and at the European Southern Observatory have joined forces to design, build and install the Laser Guide Star Facility for the VLT. The Laser Guide Star Facility has now been completed and installed on the VLT Yepun telescope at Cerro Paranal. In this paper we report on the first light and first results from the Commissioning of the LGSF.

The Simultaneous Multiple Surface (SMS) method in 3D geometry is presented. Giving two orthotomic input ray bundles and other two orthotomic output ray bundles, the method provides an optical system with two free-form surfaces that deflects the rays of the input bundles into the rays of the corresponding output bundles and vice versa. In nonimaging applications, the method allows controlling the light emitted by an extended light source much better than single free-form surfaces designs, and also enables the optics contour to be shaped without efficiency losses. The method is expected to find also applications in imaging optics

In this work it is presented a new design of a TIR lens-mushrooms lens device developed with the Simultaneous Multiple Surfaces (SMS) method. In SMS nomenclature, it is named TIR-R. In contrast to previous TIR-mushroom designs, application of the SMS method to this configuration consists in the simultaneous design of both TIR (total internal reflection) and R (refraction) optical surfaces using extended ray-bundles and the edge-ray theorem. In this paper is presented a basic approach to do the design. In this basic approach, first it is considered the TIR lens as a microstructured surface with infinitesimal flat facets. Afterwards, it is generated a TIR lens with finite size facets from the already designed one. In an advanced approach could be considered the TIR lens with finite facet size and designed simultaneously each facet with a portion of the outer surface of the mushroom lens. With respect to others SMS high-gain devices (as the RXI), the TIR-R concentrator has the following advantages: is a mirror-less device, there is not shadowing elements, and the receiver/emitter element's placement is more favorable for encapsulation and electrical connection. As it is common in the SMS devices, the TIR-R concentrator achieves wide acceptance angle and high efficiency with a low aspect ratio (thickness to entry aperture diameter ratio). For example, a 1256X concentration device has a theoretical efficiency of 100 percent (without optical losses) with an acceptance angle of +/- 1.7 decgrees, and an aspect ratio of 0.34.

Advanced optical design methods using the keys of nonimaging optics lead to some ultra compact designs which combine the concentrating (or collimating) capabilities of conventional long focal length systems with a high collection efficiency. One of those designs is the so-called RXI. Its aspect ratio (thickness/aperture diameter) is less than 1/3. Used as a receiver, i.e. placing a photodiode at the proper position, it gets an irradiance concentration of the 95% of the theoretical thermodynamic limit (this means for example, a concentration of 1600 times with an acceptance angle of +/- 2.14 degrees). When used as an emitter (replacing the aforementioned photodiode by an LED, for instance), similar intensity gains may be obtained within an angle cone almost as wide as the 95% of the thermodynamic limit. In a real device these irradiance(and intensity)gains are reduced by the optical efficiency. This combination of high concentration factors, relatively wide angles, simplicity and compactness make the optical device almost unique. This work will show the results of the measurements done with several RXI prototypes of 40-mm aperture diameter, all of them made of PMMA (by injection process).

The purpose of this work is to present the measurements of the main characteristics of a series of RXI concentrators developed: angular transmission, acceptable angle, optical efficiency, and optical concentration. The RXI concentrator has been designed with the Simultaneous Multiple Surfaces method developed by Minano et al. at the Instituto de Energia Solar--Universidad Politecnica de Madrid. The design characteristics are: geometric concentration 1256X, acceptance angle 1.8 degree(s).© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.