Gemini multiconjugate adaptive optics system review - I. Design, trade-offs and integration

The Gemini multiconjugate adaptive optics system (GeMS) at the Gemini South telescope in Cerro Pachón is the first sodium-based multilaser guide star (LGS) adaptive optics system. It uses five LGSs and two deformable mirrors to measure and compensate fo

Gemini multi-conjugate adaptive optics system review II: Commissioning, operation and overall performance

The Gemini Multi-conjugate Adaptive Optics System - GeMS, a facility instrument mounted on the Gemini South telescope, delivers a uniform, near diffraction limited images at near infrared wavelengths (0.95 microns- 2.5 microns) over a field of view of 120 arc seconds. GeMS is the first sodium layer based multi laser guide star adaptive optics system used in astronomy. It uses five laser guide stars distributed on a 60 arc seconds square constellation to measure for atmospheric distortions and two deformable mirrors to compensate for it. In this paper, the second devoted to describe the GeMS project, we present the commissioning, overall performance and operational scheme of GeMS. Performance of each sub-system is derived from the commissioning results. The typical image quality, expressed in full with half maximum, Strehl ratios and variations over the field delivered by the system are then described. A discussion of the main contributor to performance limitation is carried-out. Finally, overheads and future system upgrades are described.Comment: 20 pages, 11 figures, accepted for publication in MNRA

Increasing sky coverage with the Gemini North ALTAIR/LGS AO system

The Gemini North (GN) AO system, Altair, has been routinely operating in LGS mode since 2007. Due to the initial optical design, the NGS field-of-view (FoV) is limited to a radius ~ 25" which limits the potential science. To improve this, we have tested the AO/LGS operation using a peripheral wavefront sensor (PWFS) whose patrol field is ~ 4'-7' from the target. This expanded NGS FoV permits greater sky coverage but with decreased resolution, FWHM ~ 0.1" - 0.2" making this mode very suitable for non-imaging spectrographic and integral field unit observations. We present the hardware and software upgrades to PWFS and Altair as well as the software necessary for making this observing mode a routine and integral part of GN operations. Characterization and performance of this new operation mode, known as LGS+P1, are presented.8 page(s

Gemini South multi-conjugate adaptive optics (GeMS) laser guide star facility on-sky performance results

With two to three deformable mirrors, three Natural Guide Stars (NGS) and five sodium Laser Guide Stars (LGS), the Gemini Multi-Conjugate Adaptive Optics System (Gemini MCAO a.k.a. GeMS) will be the first facility-class MCAO capability to be offered for regular science observations starting in 2013A. The engineering and science commissioning phase of the project was kicked off in January 2011 when the Gemini South Laser Guide Star Facility (GS LGSF) propagated its 50W laser above the summit of Cerro Pachón, Chile. GeMS commissioning has proceeded throughout 2011 and the first half of 2012 at a pace of one 6- to 10-night run per month with a 5-month pause during the 2011 Chilean winter. This paper focuses on the LGSF-side of the project and provides an overview of the LGSF system and subsystems, their top-level specifications, design, integration with the telescope, and performance throughout commissioning and beyond. Subsystems of the GS LGSF include: (i) a diode-pumped solid-state 1.06+1.32 micron sum-frequency laser capable of producing over 50W of output power at the sodium wavelength (589nm); (ii) Beam Transfer Optics (BTO) that transport the 50W beam up the telescope, split the beam five-ways and configure the five 10W beams for projection by the Laser Launch Telescope (LLT) located behind the Gemini South 8m telescope secondary mirror; and (iii) a variety of safety systems to ensure safe laser operations for observatory personnel and equipment, neighbor observatories, as well as passing aircrafts and satellites

Altair at Gemini North : full sky coverage laser AO correction at visible wavelengths

We present two recent upgrades to the Gemini North Adaptive Optics (AO) system, Altair. These two upgrades provide 100% sky coverage for low performance AO suitable for improving the natural seeing by factors of 25% to 3 from blue visible wavelengths (350 nm) through the near infrared (2.5 micron wavelengths). The first upgrade, dubbed LGS + P1 "Super Seeing" mode, allows correction of high order aberrations with an on-axis Laser Guide Star (LGS) while tip/tilt correction is performed with a more distant peripheral wavefront sensor (P1). Most currently operating LGS AO systems are limited in their sky coverage, primarily due to tip/tilt star availability. Although P1 provides sub-optimal tip/tilt correction due to its distance from the science source, its patrol radius allows operation in LGS + P1 mode anywhere in the sky from declinations of +70 degrees to -30 degrees. This mode was offered for science use at Gemini North in 2013A. We present typical performance and use from its first semester in science operation, with a factor 2 to 3 image quality improvement over seeing limited images. The second upgrade is the commissioning of the AO system to correct at visible wavelengths, which is expected to be completed in 2014. In this mode, Altair will feed the Gemini Multi-Object Spectrograph (GMOS), which is an optical imager as well as a long-slit, multi-slit and integral field unit spectrograph. We intend to replace the current Altair science dichroic with a sodium notch filter, passing only the 589nm wavelength light from the LGS to the AO system. The rest of the spectrum from 350 nm to the GMOS red cutoff at 1.1 microns is intended as science capable light. Tip/tilt correction will be performed close to the science target with the GMOS on-instrument wavefront sensor or with P1 as in the P1+LGS mode discussed above. We expect an image quality improvement of 25% in this mode over seeing limited observations. Since exposure time to reach a given signal-to-noise ratio scales roughly as the square of the image quality, these two upgrades represent a substantial efficiency improvement which is available to nearly all targets normally observed at Gemini North.7 page(s

Getting ready for GeMS 2.0: A workhorse AO facility

AO systems aim at detecting and correcting for optical distortions induced by atmospheric turbulences. The Gemini South telescope has currently two main AO systems: the Gemini Multi Conjugated AO System GeMS and the Gemini Planet Imager GPI. GeMS is operational and regularly used for science observation delivering close to diffraction limit resolution over a large field of view (85-85 arcsec2). We first review the performance obtained this past year. Then we will go in the details of the strong modifications GeMS is currently having. We are integrating a new laser system in the laser guide star facility module. We are also advancing in the development of the new Natural Guide Star wavefront sensor. We present as well in this paper the preliminary results obtained with our new installed NGS mask that allows us better astrometric precision.Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States of America), The National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Minist´erio de Ciˆencia, Tecnologia e Inova¸c˜ao (Brazil) and Ministerio de Ciencia, Tecnologia e Innovaci´on Productiva (Argentina)

An infusion of new blood using the Toptica laser with GeMS: results of the commissioning and science performance

International audienc

Gemini-north multiobject spectrograph integration, test, and commissioning

NRC publication: Ye

Gemini multiconjugate adaptive optics system review - II. Commissioning, operation and overall performance

The Gemini multiconjugate adaptive optics system-GeMS, a facility instrument mounted on the Gemini South telescope, delivers a uniform, near diffraction limited images at near-infrared wavelengths (0.95-2.5 μm) over a field of view of 120 arcsec. GeMS i