TMT NFIRAOS: adaptive optics system for the Thirty Meter Telescope

Herriot, Glen; Andersen, David; Atwood, Jenny; Byrnes, Peter; Boucher, Marc-André; Boyer, Corinne; Caputa, K.; Correia, Carlos; Dunn, Jennifer; Ellerbroek, Brent L.; Fitzsimmons, Joeleff; Gilles, Luc; Hickson, Paul; Hill, Alexis; Kerley, Dan; Pazder, John; Решетов, В. А.; Roberts, Scott; Smith, Malcolm J.; Véran, Jean-Pierre; Wang, Lianqi; Wevers, Ivan

doi:10.1117/12.925087

Cited by 15 publications

(13 citation statements)

References 5 publications

(5 reference statements)

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“…However, large-scale efforts are underway to design MCAO systems for the next generation of ELTs, which will have a diameter between 20 and 40 m. These include MAORY for the European ELT (E-ELT) [13] and the first light NFIR-AOS for the thirty-meter telescope (TMT) [14,15]. Although not currently under design, a MCAO system for the giant magellan telescope (GMT) is not precluded [16].…”

Section: Current and Future Instrumentsmentioning

confidence: 99%

Increased sky coverage with optimal correction of tilt and tilt-anisoplanatism modes in laser-guide-star multiconjugate adaptive optics

et al. 2013

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Laser-guide-star multiconjugate adaptive optics (MCAO) systems require natural guide stars (NGS) to measure tilt and tilt-anisoplanatism modes. Making optimal use of the limited number of photons coming from such, generally dim, sources is mandatory to obtain reasonable sky coverage, i.e., the probability of finding asterisms amenable to NGS wavefront (WF) sensing for a predefined WF error budget. This paper presents a Strehl-optimal (minimum residual variance) spatiotemporal reconstructor merging principles of modal atmospheric tomography and optimal stochastic control theory. Simulations of NFIRAOS, the first light MCAO system for the thirty-meter telescope, using ∼500 typical NGS asterisms, show that the minimum-variance (MV) controller delivers outstanding results, in particular for cases with relatively dim stars (down to magnitude 22 in the H-band), for which lowtemporal frame rates (as low as 16 Hz) are required to integrate enough flux. Over all the cases tested ∼21 nm rms median improvement in WF error can be achieved with the MV compared to the current baseline, a type-II controller based on a double integrator. This means that for a given level of tolerable residual WF error, the sky coverage is increased by roughly 10%, a quite significant figure. The improvement goes up to more than 20% when compared with a traditional single-integrator controller.

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Section: Current and Future Instrumentsmentioning

confidence: 99%

Increased sky coverage with optimal correction of tilt and tilt-anisoplanatism modes in laser-guide-star multiconjugate adaptive optics

et al. 2013

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“…It is discussed in detail in other papers [1] [2] . For the purposes of real-time control, NFIRAOS contains two deformable mirrors, one tip/tilt stage, six Shack-Hartmann LGS WFS (laser guide star wavefront sensors) and one natural guide star pyramid WFS.…”

Section: Nfiraosmentioning

confidence: 99%

Thirty Meter Telescope narrow-field infrared adaptive optics system real-time controller prototyping results

Smith

Kerley

Chapin

et al. 2016

Adaptive Optics Systems V

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Prototyping and benchmarking was performed for the Real-Time Controller (RTC) of the Narrow Field InfraRed Adaptive Optics System (NFIRAOS). To perform wavefront correction, NFIRAOS utilizes two deformable mirrors (DM) and one tip/tilt stage (TTS). The RTC receives wavefront information from six Laser Guide Star (LGS) ShackHartmann WaveFront Sensors (WFS), one high-order Natural Guide Star Pyramid WaveFront Sensor (PWFS) and multiple low-order instrument detectors. The RTC uses this information to determine the commands to send to the wavefront correctors. NFIRAOS is the first light AO system for the Thirty Meter Telescope (TMT).The prototyping was performed using dual-socket high performance Linux servers with the real-time (PREEMPT_RT) patch and demonstrated the viability of a commercial off-the-shelf (COTS) hardware approach to large scale AO reconstruction. In particular, a large custom matrix vector multiplication (MVM) was benchmarked which met the required latency requirements. In addition all major inter-machine communication was verified to be adequate using 10Gb and 40Gb Ethernet. The results of this prototyping has enabled a CPU-based NFIRAOS RTC design to proceed with confidence and that COTS hardware can be used to meet the demanding performance requirements.

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“…where the factor of M(1, Dν) is included to filter out the tip/tilt/piston modes of the wavefront error on a circular aperture of diameter D. Figure 1 plots this sensitivity function (in units of μas per nm) for quasi-static wavefront errors on the deformable mirror DM11.2 in the NFIRAOS first light AO system for the Thirty Meter Telescope (Herriot et al 2012). The relevant parameter values for this instrument are D = 30 m, ρ = 30 arcsec, h j = 11.2 km, and N = 0 or 1.…”

Section: Quasi-static Errorsmentioning

confidence: 99%

A Fourier domain model for estimating astrometry errors due to static and quasi-static optical surface errors

Ellerbroek

2013

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Context. The wavefront aberrations due to optical surface errors in adaptive optics systems and science instruments can be a significant error source for high precision astrometry. Aims. This report derives formulas for evaluating these errors which may be useful in developing astrometry error budgets and optical surface quality specifications. Methods. A Fourier domain approach is used, and the errors on each optical surface are modeled as "phase screens" with stationary statistics at one or several conjugate ranges from the optical system pupil. Three classes of error are considered: (i) errors in initially calibrating the effects of static surface errors; (ii) the effects of beam translation, or "wander," across optical surfaces due to (for example) instrument boresighting error; and (iii) quasistatic surface errors which change from one observation to the next. Results. For each of these effects, we develop formulas describing the position estimation errors in a single observation of a science field, as well as the differential error between two separate observations. Sample numerical results are presented for the three classes of error, including some sample computations for the Thirty Meter Telescope and the NFIRAOS first-light adaptive optics system.

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TMT NFIRAOS: adaptive optics system for the Thirty Meter Telescope

Cited by 15 publications

References 5 publications

Increased sky coverage with optimal correction of tilt and tilt-anisoplanatism modes in laser-guide-star multiconjugate adaptive optics

Increased sky coverage with optimal correction of tilt and tilt-anisoplanatism modes in laser-guide-star multiconjugate adaptive optics

Thirty Meter Telescope narrow-field infrared adaptive optics system real-time controller prototyping results

A Fourier domain model for estimating astrometry errors due to static and quasi-static optical surface errors

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