Status report on the Large Binocular Telescope's ARGOS ground-layer AO system

Hart, Michael; Rabien, S.; Busoni, Lorenzo; Beckmann, U.; Bonaglia, Marco; Boose, Yvonne; Borelli, J. L.; Bluemchen, T.; Carbonaro, Luca; Connot, C.; Deysenroth, M.; Davies, Richard; Durney, Olivier; Elberich, M.; Ertl, Thomas; Esposito, Simone; Gäessler, Wolfgang; Gasho, Victor; Gemperlein, Hans; Hubbard, P.; Kanneganti, S.; Kulas, M.; Newman, K.; Noenickx, Jamison; Xivry, Gilles Orban de; Peter, D.; Quirrenbach, A.; Rademacher, Matt; Schwab, Christian; Storm, J.; Vaitheeswaran, Vidhya; Weigelt, G.; Ziegleder, J.

doi:10.1117/12.893916

Cited by 5 publications

(3 citation statements)

References 12 publications

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“…Two types of lasers: Na LGS and Rayleigh scattering LOS are used by major observatories, either one kind or more recently a combination of both in LBT (5). A useful tabulation of Na LGS was published by D. Gavel (6).…”

Section: Comparison Of Major Observatory Performancementioning

confidence: 99%

Multiple laser guide stars (LGS) for multiple conjugate adaptive optics (MCAO)

Jones¹

2012

SPIE Proceedings

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For wavefront sensing and control, the most extensive use of Mult-Conjugate Adaptive Optics (MCAO) systems for extended-path aberration compensation lies with the use of multiple Laser Guide Stars (LGS) for Multi-Conjugate Adaptive Optics (MCAO). Ground-based adaptive optics systems were initially developed by the Starfire Optical Range (SOR) in 1983. Both Rayleigh guide stars and Na laser guide stars have been developed. More recently, both laser systems, Na LGS at 93 km and Rayleigh guide stars at 20 km, are being combined in the Large Binocular Teslecope (LBT) for multiple LGS for Multiple Conjugate Adaptive Optics (MCAO) (M. Hart et al, 2011). Each side of the LBT has 3 Rayleigh LGS which are projected into two triangular constellations. A sodium LGS will be added to each aperture using the same launch optics as the Rayleigh beacons. This will combine low altitude Rayleigh LGS and high altitude Na laser guide stars into a uniquely powerful tomographic wavefront sensing system of Multi-Conjugate Adaptive Optics.Other observatories have used either Rayleigh guide stars or Na guide stars. ESO VLT has 4 Na LGS. MMT has 5 Rayleigh guide stars. Gemini Multi-Conjugate Adaptive Optics System (GEMS) has 5 Na LGS. The many multiple LGS MCAO observatories will be compared for effective design and projected performance.

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Section: Comparison Of Major Observatory Performancementioning

confidence: 99%

Multiple laser guide stars (LGS) for multiple conjugate adaptive optics (MCAO)

Jones¹

2012

SPIE Proceedings

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“…2 Especially, ARGOS will reduce the observation time for the same signal-to-noise ratio in the spectroscopy mode. Besides the six lasers, the ARGOS hardware equipment contains several other devices like calibration sources, slope computers, cameras and motors.…”

Section: Laser Guide Star System Argosmentioning

confidence: 99%

Practical experience with test-driven development during commissioning of the multi-star AO system ARGOS

et al. 2014

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Commissioning time for an instrument at an observatory is precious, especially the night time. Whenever astronomers come up with a software feature request or point out a software defect, the software engineers have the task to find a solution and implement it as fast as possible. In this project phase, the software engineers work under time pressure and stress to deliver a functional instrument control software (ICS). The shortness of development time during commissioning is a constraint for software engineering teams and applies to the ARGOS project as well. The goal of the ARGOS (Advanced Rayleigh guided Ground layer adaptive Optics System) project is the upgrade of the Large Binocular Telescope (LBT) with an adaptive optics (AO) system consisting of six Rayleigh laser guide stars and wavefront sensors. For developing the ICS, we used the technique TestDriven Development (TDD) whose main rule demands that the programmer writes test code before production code. Thereby, TDD can yield a software system, that grows without defects and eases maintenance. Having applied TDD in a calm and relaxed environment like office and laboratory, the ARGOS team has profited from the benefits of TDD. Before the commissioning, we were worried that the time pressure in that tough project phase would force us to drop TDD because we would spend more time writing test code than it would be worth. Despite this concern at the beginning, we could keep TDD most of the time also in this project phase This report describes the practical application and performance of TDD including its benefits, limitations and problems during the ARGOS commissioning. Furthermore, it covers our experience with pair programming and continuous integration at the telescope.Keywords: Test-Driven Development, TDD, commissioning, continuous integration, pair programming, software engineering, testing, instrument control software, distributed software system, adaptive optics, LBT SET UPThe goal of the multi-star AO system ARGOS is improving the image quality for the imager and spectrograph LUCI. In order to run a complex distributed hardware system like ARGOS, the telescope operators require assistance from the instrument control software (ICS) that the software engineers have to develop partly at the telescope on the mountain under the harsh conditions of an instrument commissioning.

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“…This finally resulted in the ARGOS instrument, which is now close to installation at the telescope. As the system was already presented several times we will not go into detail of the science capabilities or performance simulation, which can be found in proceedings of previous conferences 5,6 .…”

Section: Introductionmentioning

confidence: 99%

Status of the ARGOS ground layer adaptive optics system

et al. 2012

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ARGOS the Advanced Rayleigh guided Ground layer adaptive Optics System for the LBT (Large Binocular Telescope) is built by a German-Italian-American consortium. It will be a seeing reducer correcting the turbulence in the lower atmosphere over a field of 2' radius. In such way we expect to improve the spatial resolution over the seeing of about a factor of two and more and to increase the throughput for spectroscopy accordingly. In its initial implementation, ARGOS will feed the two near-infrared spectrograph and imager -LUCI I and LUCI II.The system consist of six Rayleigh lasers -three per eye of the LBT. The lasers are launched from the back of the adaptive secondary mirror of the LBT. ARGOS has one wavefront sensor unit per primary mirror of the LBT, each of the units with three Shack-Hartmann sensors, which are imaged on one detector.In 2010 and 2011, we already mounted parts of the instrument at the telescope to provide an environment for the main sub-systems. The commissioning of the instrument will start in 2012 in a staged approach. We will give an overview of ARGOS and its goals and report about the status and new challenges we encountered during the building phase. Finally we will give an outlook of the upcoming work, how we will operate it and further possibilities the system enables by design.

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Status report on the Large Binocular Telescope's ARGOS ground-layer AO system

Cited by 5 publications

References 12 publications

Multiple laser guide stars (LGS) for multiple conjugate adaptive optics (MCAO)

Multiple laser guide stars (LGS) for multiple conjugate adaptive optics (MCAO)

Practical experience with test-driven development during commissioning of the multi-star AO system ARGOS

Status of the ARGOS ground layer adaptive optics system

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