Main goal of this study is to compare the performances of a full line of LCD diagnostic display systems, in terms of
white point luminance, accuracy and stability over time, GSDF conformance and luminance uniformity, and to test a
web-based service for remote calibration and QA in a large hospital. The display systems under test included 3MP and
5MP grayscale, 2MP and 6MP color and 5MP mammography LCD monitors, all manufactured by BARCO, for a total
amount of 119 units. Measured performances were all within the acceptance range proposed by the major international
protocols and show a very good stability in time, except for a few cases. The web-based service for remote QA and
calibration resulted well suited for the management of a large scale medical facility, where high performance displays are
in use and time saving QA programs and a central QA policy are both needed.
The paper is describing the present status of the LBT first light AO system. The system design started in January 2002 and is now approaching the final test in the Arcetri solar tower. Two key features of this single conjugate AO system are the use of an adaptive secondary mirror having 672 actuators and a pyramid wavefront sensor with a maximum sampling of 30x30 subapertures. The paper is reporting about the adaptive secondary mechanical electrical and optical integration, and the wavefront sensor unit integration and acceptance test. Finally some lab test of the AO system done using an adaptive secondary prototype with 45 actuators, the so called P45 are described. The aim of these test was to get an estimate of the system limiting magnitude and to demonstrate the feasibility of a new technique able to measure AO system interaction matrix in a shortest time and with higher SNR with respect to the classical interaction matrix measurement. We are planning to use such a technique to calibrate the AO system in Arcetri and later at the LBT telescope.
AMBER is the focal near-infrared instrument of the VLTI combining
2 or 3 telescopes in the J, H and K bands with 3 spectral resolution modes. It uses single-mode fibers to ensure modal filtering and high measurement accuracies. AMBER has been integrated and tested in Grenoble during 2003. We report in this paper the lab performances of the instrument in terms of instrumental contrast, measurement accuracy and stability, and throughput.
The two 911mm-diameter adaptive secondary (AS) mirrors for the Large Binocular telescope (LBT) are currently under construction. The design of the units has been based on the extensive experience made on the MMT adaptive secondary mirror during laboratory tests and telescope runs. Mechanics, electronics and control logic have been revised to improve performances and reliability. Each unit has 672 electro-magnetic force actuators. They control the figure of the Gregorian secondary 1.6mm-thick mirrors with an internal loop using the signal of co-located capacitive sensors. The improvement in the computational power of the on-board control electronics allows to use it as real-time computer for wavefront reconstruction. We present the progress of the final unit construction and the preliminary laboratory results obtained with a 45-actuator
sub-system used to test the new features introduced in the electronics and mechanics of LBT adaptive secondary mirrors.
The instrumentation for VLT/VLTI 1 facility of the European Southern Observatory at Paranal (Chile)includes the infrared beam-combiner called AMBER, that covers the near infrared bands up to 2.5 μm. The cold spectrograph we describe is the AMBER subsystem responsible of wavelength analysis and several other functions, all of them performed by means of optics, analyzers, and mechanisms working at the temperature of liquid nitrogen boiling at atmospheric pressure. The cryo-mechanical design of the spectrograph we describe here
used extensively the methods of finite element analysis and the laboratory tests validated this approach. The final optical quality we measured in the laboratory before shipping the instrument to Grenoble or integration (December 2002),is well inside the specification the AMBER staff assigned to the spectrograph. Simulations show that its total contribution to visibility loss of AMBER is less than 2%.