On the isoplanatic patch size in stellar speckle interferometry

Roddier, F.; Gilli, J. M.; Vernin, J.

doi:10.1088/0150-536x/13/2/002

Cited by 46 publications

(28 citation statements)

References 13 publications

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“…6 will be affected by the range of values of h present but no overall qualitative change in isoplanaticity is expected, since the same argument regarding the correlation scale applies for all the layers. This conclusion may appear to conflict with the results of Roddier et al (1982) in their analysis of the isoplanatic patch size in speckle interferometry. They obtain an isoplanatic angular size ∼D/h for a single thin turbulent layer but ∼r 0 /∆h for a thick layer of thickness ∆h.…”

Section: Isoplanatismmentioning

confidence: 72%

The point spread function in Lucky Imaging and variations in seeing on short timescales

Baldwin

Warner

Mackay³

2008

A&A

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Aims. We investigate the properties of astronomical images made by combining the best images selected from a sequence of shortexposure frames (Lucky Imaging); we assess the match between modelling and observation and discover what variations in seeing occur on very short timescales. Methods. Numerical simulations of a random phase-changing screen passing across a telescope aperture with ideal optics are used to determine the expected point spread function and isoplanatic properties for a range of seeing conditions for comparison with observations. Results. All the model images comprise a diffraction-limited core with Strehl ratios from 0.05-0.5 and an underlying broad disk. The isoplanatic patch sizes are large and coherence times long. The observations are a close match to the models in most respects. Large variations in seeing occur on temporal scales as short as 0.2 s and spatial scales as small as 1 m.

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Section: Isoplanatismmentioning

confidence: 72%

The point spread function in Lucky Imaging and variations in seeing on short timescales

Baldwin

Warner

Mackay³

2008

A&A

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“…On the other hand, it was established that the scintillation index σ 2 I (the normalized intensity variance) is also related to the C 2 n profile (Roddier 1982)…”

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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“…The GSM experiment [33,31] reveals that its values lay between few tenths to few hundreds meters (10-300 m) for nighttime observations while they are no measurements or very few for daytime observations. The isoplanatic patch can be estimated from the atmospheric turbulence profiles [17,34] or interferogramm cross-correlation of double stars [34]. They are fewer measurements for daytime observations.…”

Section: Parameter Estimation Of the Observation Conditionsmentioning

confidence: 99%

Atmospheric Turbulence and Solar Diameter Measurement

Irbah

Bouzid

Lakhal

et al. 2003

The Sun’s Surface and Subsurface

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Abstract. Object images obtained by mean of ground based instrument are degraded by the earth atmosphere. Indeed, the wave-front at the entrance of the instrument pupil, present phase and amplitude random fluctuations depending of the time, the position and the line of sight. The recorded images are consequently filtered leading to bad measurements of the studied object parameters. To qualify the atmospheric degradations, several parameters are commonly defined. For solar diameter measurements performed with an astrolabe, errors due to the atmospheric turbulence are directly related to these parameters. After, a brief recall of the basic properties of the atmospheric turbulence, a method allowing to generate realistic random wave-fronts will be presented. They will be used to study errors on diameter measurements performed with a solar astrolabe. The obtained results will clearly show the necessity to have a seeing monitor observing together with the solar experiment. A method allowing to obtain the observation conditions for solar observation will then be given.

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On the isoplanatic patch size in stellar speckle interferometry

Cited by 46 publications

References 13 publications

The point spread function in Lucky Imaging and variations in seeing on short timescales

The point spread function in Lucky Imaging and variations in seeing on short timescales

Multi-instrument measurement campaign at Paranal in 2007

Atmospheric Turbulence and Solar Diameter Measurement

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