MACAO-VLTI adaptive optics systems performance

Arsenault, Robin; Donaldson, Rob; Dupuy, Christophe; Fedrigo, Enrico; Hubin, N.; Ivanescu, Liviu; Kasper, Markus; Oberti, Sylvain; Paufique, J.; Rossi, Silvio; Silber, A.; Delabre, B.; Lizon, Jean-Louis; Gigan, P.

doi:10.1117/12.552548

Cited by 31 publications

(17 citation statements)

References 6 publications

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“…A range of 30 pixels, mainly driven by AOCS low frequency drifting, corresponds to an amplitude of 42 μrad. These requirements are roughly in agreement with the features of the FSM developed by Gigan [1].…”

Section: Noordwijk Netherlands 27-30 June 2006supporting

confidence: 77%

Numerical line of sight stabilisation for high resolution earth observation from high orbits

Blanc¹,

Monroig²

2017

International Conference on Space Optics — ICSO 2006

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Section: Noordwijk Netherlands 27-30 June 2006supporting

confidence: 77%

Numerical line of sight stabilisation for high resolution earth observation from high orbits

Blanc¹,

Monroig²

2017

International Conference on Space Optics — ICSO 2006

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“…Figure 9 gives a simplified overview of the interferometer control system, when used in conjunction with either FSUA or FSUB. The target is observed with two ATs or two UTs, providing field stabilisation with a tip-tilt system (Koehler et al 2006) or adaptive optics (Arsenault et al 2004), respectively. Mirrors guide the telescope beams through optical delay lines into the beam combination laboratory, where the H-band beams are fed into the angle-tracking camera (Gitton et al 2004) and the K-band beams enter the FSU.…”

Section: Fsu Fringe Trackingmentioning

confidence: 99%

“…Four stars were observed with UT3 and UT4 and fringes were observed with FSUA. The adaptive optics systems (Arsenault et al 2004) and the vibration cancellation system based on accelerometers were enabled. Fringe tracking was achieved for three stars with minimum brightness of m K = 8.6, for the fourth star with apparent magnitude m K = 11.7 fringes were detected but not tracked (Table 6).…”

Section: Fringe-tracking With Utsmentioning

confidence: 99%

The PRIMA fringe sensor unit

Ménardi¹,

Abuter²,

Accardo³

et al. 2009

A&A

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Context. The fringe sensor unit (FSU) is the central element of the phase referenced imaging and micro-arcsecond astrometry (PRIMA) dual-feed facility and provides fringe sensing for all observation modes, comprising off-axis fringe tracking, phase referenced imaging, and high-accuracy narrow-angle astrometry. It is installed at the Very Large Telescope Interferometer (VLTI) and successfully served the fringe-tracking loop during the initial commissioning phase. Aims. To maximise sensitivity, speed, and robustness, the FSU is designed to operate in the infrared K-band and to include spatial filtering after beam combination and a very-low-resolution spectrometer without photometric channels. It consists of two identical fringe sensors for dual-star operation in PRIMA astrometric mode. Methods. Unique among interferometric beam combiners, the FSU uses spatial phase modulation in bulk optics to retrieve real-time estimates of fringe phase after spatial filtering. The beam combination design accommodates a laser metrology for pathlength monitoring. An R = 20 spectrometer across the K-band makes the retrieval of the group delay signal possible. The calibration procedure uses the artificial light source of the VLTI laboratory and is based on Fourier transform spectroscopy to remove instrumental effects. Results. The FSU was integrated and aligned at the VLTI in July and August 2008. It yields phase and group delay measurements at sampling rates up to 2 kHz, which are used to drive the fringe-tracking control loop. During the first commissioning runs, the FSU was used to track the fringes of stars with K-band magnitudes as faint as m K = 9.0, using two VLTI auxiliary telescopes (AT) and baselines of up to 96 m. Fringe tracking using two Very Large Telescope (VLT) unit telescopes was demonstrated. Conclusions. The concept of spatial phase-modulation for fringe sensing and tracking in stellar interferometry is demonstrated for the first time with the FSU. During initial commissioning and combining stellar light with two ATs, the FSU showed its ability to improve the VLTI sensitivity in K-band by more than one magnitude towards fainter objects, which is fundamental for achieving the scientific objectives of PRIMA.

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“…The spectrograph provides a resolution of up to 100 000 at 960-5200 nm with an instantaneous wavelength coverage of ∼λ/50 on a 4096 × 512 pixel detector mosaic (Käufl et al 2004(Käufl et al , 2006b. A MACAO 2 adaptive optics system (Arsenault et al 2004) provides diffraction limited images at the entrance slit of CRIRES with Strehl ratios of up to 65% in the K band, thus roughly doubling the throughput under reasonable seeing conditions for the nominal 0.2 slit when compared to seeing-limited performance (Paufique et al 2006).…”

Section: Criresmentioning

confidence: 99%

High precision radial velocity measurements in the infrared

Seifahrt

Käufl²

2008

A&A

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High precision radial velocity (RV) measurements in the near infrared are in high demand, especially in the context of exoplanet search campaigns shifting their interest to late type stars in order to detect planets with ever lower mass or targeting embedded pre-main-sequence objects. ESO commissioned a new spectrograph at the VLT -CRIRES -designed for high resolution near-infrared spectroscopy with a comparably broad wavelength coverage and the possibility of using gascells to provide a stable RV zero-point. Here, we investigate the intrinsic short-term RV stability of CRIRES, both with gascell calibration data and on-sky measurements using the absorption lines of the Earth's atmosphere imprinted in the source spectrum as a local RV rest frame. Moreover, we also investigate for the first time the intrinsic stability of telluric lines at 4100 nm for features originating in the lower troposphere. Our analysis of nearly 5 h of consecutive observations of MS Vel, a M2II bright giant centred on two SiO first overtone band-heads at 4100 nm, demonstrates that the intrinsic short-term stability of CRIRES is very high, showing only a slow and fully compensateable drift of up to 60 m/s after 4.5 h. The radial velocity of the telluric lines is constant down to a level of approx. ±10 m/s (or 7/1000 of one pixel). Utilising the same telluric lines as a rest frame for our radial velocity measurements of the science target, we obtain a constant RV with a precision of approx. ±20 m/s for MS Vel, as expected for a M-giant.

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MACAO-VLTI adaptive optics systems performance

Cited by 31 publications

References 6 publications

Numerical line of sight stabilisation for high resolution earth observation from high orbits

Numerical line of sight stabilisation for high resolution earth observation from high orbits

The PRIMA fringe sensor unit

High precision radial velocity measurements in the infrared

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