Paper
21 February 2003 Commissioning of the VLTi delay lines on Mount Paranal
Harm Hogenhuis, Martijn Visser, Frederic Derie
Author Affiliations +
Abstract
This paper will provide details of the outstanding performance of the VLTi Delay Lines in Blind Tracking and Fringe Tracking modes. This OPD control performance was demonstrated during the first fringe event in October last year where two UTs (ANTU and MELIPAL) were combined by the interferometer. Already in March 2001 the fringes were observed by the VLT interferometer equipped, at this time, with two Siderostats. The stellar light was collected and trasported via the Delay Lines to the VINCI instrument, also used as fringe detector. The excellent results were achieved after several missions on the mountain, managed by ESO and DUTCH SPACE personnel, to install and to verify the tracking performance of the first three Delay Lines over the full length of the tracks and to align the science beams over the Delay Lines reflectors. The first performance tests were done in open loop (without a fringe sensor feedback to the Delay Line) by imposing a global trajectory on the active Delay Line. During the commissioning period with the Siderostats, this procedure was a success and provided already encouraging results. In a later stage of the Delay Line commissioning, the Fringe Acquisition and Tracking Mode enabling to keep closed loop performance for longer periods each night replaced the Blind Tracking Mode. Performance monitoring during various occasions after installation revealed that OPD errors are not degrading in time; extensive preventive maintenance activities are not required to keep the performance levels within specifications, proving the robustness of the controller of the Delay Line.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Harm Hogenhuis, Martijn Visser, and Frederic Derie "Commissioning of the VLTi delay lines on Mount Paranal", Proc. SPIE 4838, Interferometry for Optical Astronomy II, (21 February 2003); https://doi.org/10.1117/12.457119
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Cited by 1 scholarly publication.
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KEYWORDS
Metrology

Interferometers

Actuators

Sensors

Telescopes

Interferometry

Control systems

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