From the grating scale monitor to the generalized seeing monitor

Ziad, Aziz; Conan, Rodolphe; Tokovinin, Andreï; Martin, F.; Borgnino, J.

doi:10.1364/ao.39.005415

Cited by 113 publications

(144 citation statements)

References 21 publications

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“…During its previous missions it was found that L 0 follows a log-normal distribution with a dispersion of log(L 0 ) of about 0.23, and, rather similar median values, ranging from 24 to 31 m, were obtained in all GSM campaigns (Ziad et al 1999). Large isolated values of L 0 , called "bursts", were also noted at all sites.…”

Section: Outer Scale Statisticssupporting

confidence: 57%

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Optical parameters relevant for High Angular Resolution at Paranal from GSM instrument and surface layer contribution

Martin

Conan

Tokovinin³

et al. 2000

Astron. Astrophys. Suppl. Ser.

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Abstract. Main atmospheric parameters characterizing the turbulence were measured at the Paranal ESO Observatory (Chile) with the Generalized Seeing Monitor (GSM) during 19 nights in November-December 1998. The median seeing for this period was 0.88 , a little worse than average, the spatial coherence outer scale of the wavefront L 0 = 22.0 m and the median isoplanatic angle θ 0 = 1.90 . A very good agreement with seeing values given by ESO DIMM was found. Effects of ground layer turbulence were estimated from measurements of temperature micro-fluctuations at several altitudes. These measurements revealed that the first 21 m above ground account for 12.5% of the total turbulent energy. Comparison between GSM and ESO DIMM values have permitted to highlight a local phenomenon which occurs sometimes at the site in the middle of the night. Statistics of the refractive index structure constant C 2 n in the surface layer is also studied.

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Section: Outer Scale Statisticssupporting

confidence: 57%

“…The actual instrument is described in Martin et al (1998b) and Tokovinin et al (1998b). Description and performance analysis are also given in Ziad et al (1999). We refer the interested readers to the reports on the previous GSM missions Tokovinin et al 1998a).…”

Section: Principle Of the Gsmmentioning

confidence: 99%

Optical parameters relevant for High Angular Resolution at Paranal from GSM instrument and surface layer contribution

Martin

Conan

Tokovinin³

et al. 2000

Astron. Astrophys. Suppl. Ser.

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“…It contains three DIMM (Differential Image Motion Monitor) telescopes (Aristidi et al 2005a), one of them on top of a 5 m high platform, and the other two at the snow surface level, being operated together in the GSM (Grating Scale Monitor) mode (Ziad et al 2000). Scintillation and isoplanatic angle measurements are also carried out.…”

Section: Introductionmentioning

confidence: 99%

On the atmosphere for astronomers above Dome C, Antarctica

et al. 2006

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This paper describes a comparison between balloon radio-soundings made in summer at the Concordia station, Dome C, Antarctica and coincident model-based meteorological analyses. The comparison allows the assessment of the reliability of the analyses in summer. This allows the use of the winter analyses within an estimated range of uncertainty, while the first in situ measurements are just becoming available. The astronomical interest is to produce an estimate of atmospheric turbulence during the Antarctic winter at this very promising site. For this work the 6-hourly ECMWF operational analyses were used, concurrently with the data obtained in situ by the radio-sounding made at Concordia with standard meteorological balloons and sondes during four summer seasons

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“…For λ = 0.5 μm, D 10 cm and h 10 km, W(h) resembles the h 5/3 dependence. Then θ 0 can be derived from the scintillation index as (Ziad et al 2000)…”

Section: Isoplanatic Anglementioning

confidence: 99%

Multi-instrument measurement campaign at Paranal in 2007

Ali

Ziad

Berdja

et al. 2010

A&A

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Aims. Within the framework of site qualification for the future European large telescope E-ELT, a campaign of measurements was carried out for ten nights in December 2007 at Paranal using six independent instruments. Methods. To characterize the optical turbulence, two techniques were used: the statistical analysis of the fluctuations of the angle of arrival and the scintillation of the observed objects which are, in this case, a single star for DIMM, GSM, and MASS, a double star for Cute-SCIDAR, and Moon limb for MOSP and LuSci. Results. The optical parameters measured in this campaign and presented here are the seeing, the isoplanatic angle, the coherence time, and the outer scale. We obtain a good agreement with the value measured in previous campaigns. We also extracted the vertical profile of the turbulence given by C 2 n (h), and the profiles of the outer scale for the first time at Paranal. A comparison of the different results that we present here allows the determination of the energy distribution in the free atmosphere, on the ground layer as well as in the first meters above ground. This reveals a significant contribution of the surface layer to the degradation of the global seeing.

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From the grating scale monitor to the generalized seeing monitor

Cited by 113 publications

References 21 publications

Optical parameters relevant for High Angular Resolution at Paranal from GSM instrument and surface layer contribution

Optical parameters relevant for High Angular Resolution at Paranal from GSM instrument and surface layer contribution

On the atmosphere for astronomers above Dome C, Antarctica

Multi-instrument measurement campaign at Paranal in 2007

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