Bandwidth considerations for tracking through turbulence

Tyler, Glenn A.

doi:10.1364/josaa.11.000358

Cited by 115 publications

(75 citation statements)

References 4 publications

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“…Other residual tip-tilt error produced by telescope as the telescope tracking error which can be corrected based on AO WFS Equation 1, obtained from [7], is used to model the tip tilt Power Spectrum Density (PSD) obtaining Figure 3 for 2 different atmospheres: GTCAO standard seeing scenario and adverse atmosphere defined previously. The adverse atmosphere produces a higher tip-tilt disturbance at all the frequencies.…”

Section: Windshake-induced Tip-tiltmentioning

confidence: 99%

Feedback control baseline for GTC adaptive optics with NGS

NuÃ±ez¹

2017

Proceedings of the Adaptive Optics for Extremely Large Telescopes 5

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Gran Telescopio Canarias Adaptive Optics (GTCAO) with NGS is a single-conjugated post-focal system with a Shack Hartmann wavefront sensor at visible wavelength, one Deformable Mirror (DM) and the telescope secondary mirror that is used to correct partially the tip-tilt. GTCAO feeds the scientific instrument FRIDA, which is an imager and integral field spectrograph with an image slicer.Bandwidth error has been calculated creating models for tip-tilt and high order optical modes. The error functions has been applied to representative atmospheric conditions that has been chosen based on sky characterization data from "Observatorio del Roque los Muchachos" such as coherence time or the guide star flux. Three different strategies are analysed for tip-tilt correction and one of them is proposed to be implemented.The main difference between the implementation in laboratory and the commissioning in telescope is the absence of the secondary mirror in the laboratory, an important element in the control loop that will off-load the DM, correcting tip-tilt perturbations at low temporal frequencies.

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Section: Windshake-induced Tip-tiltmentioning

confidence: 99%

Feedback control baseline for GTC adaptive optics with NGS

NuÃ±ez¹

2017

Proceedings of the Adaptive Optics for Extremely Large Telescopes 5

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“…This is also called a first-order correction involving the removal of the random displacements of the image, also referred to as tip-tilt correction. Tyler demonstrated that the bandwidth required for tiptilt correction is about nine times lower than that required for complete atmospheric compensation [3]. The main effect of optical turbulence on a beam of diameter D is the creation of phase aberrations, for which the aberration variances can be shown to be proportional to the ratio of pupil diameter to the Fried coherence length [4],…”

Section: Tip/tilt Mirrormentioning

confidence: 99%

Auxiliary free space optical communication project to ensure continuous transfer of data for DAG the 4m telescope

Keskin

Yeşilyaprak

Yerli³

2016

SPIE Proceedings

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The continuity of the amount of data that the 4m DAG (Eastern Anatolia Observatory in Turkish) telescope will produce and transfer to Ataturk University is critical not to jeopardize the science programs. Though t he fiber optics and radio link infrastructures are in place, these systems are still volatile against earthquakes, and possible excavation damages. Thus the 4m DAG telescope will be equipped with a free space optical communication system to ensure the continuity of the data transfer as a backup system. In order to cope with the disturbances introduced by the atmospheric turbulence, the transceiver FSO system will be equipped with a wavefront corrector. In this paper, the Cassegrain optical design, and working principle of this system as well as expected performance analyses will be presented.

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“…In a real system a time delay error will limit the degree of compensation [Roddiet et al, 1993 [Tyler, 1994] is the relevant parameter, rather than the Greenwood frequency [Greenwood, 1977], which is most commonly used in the adaptive optics literature.…”

Section: A Conceptual Tilt Correction Techniquementioning

confidence: 99%

Predicting the effects of anomalous refraction on the telescope point spread function: Tip‐tilt compensation at millimeter wavelengths

Olmi¹

2000

Radio Science

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Abstract. Radio-seeing effects on centimeter-and millimeter-wavelength interferometers are now reasonably well known. On the other hand, radio seeing also shows up on filledaperture telescopes as an anomalous refraction, i.e., an apparent displacement of a radio source from its true position. The magnitude of this effect, as a fraction of the beam width, is bigger on larger telescopes, and thus its impact on the pointing is likely to become critically important in the next generation of electrically large filled-aperture radio telescopes (D/A • 3-5 x 10 4, where D is the diameter). Also, because of the increasing number of focal plane arrays being used for both spectroscopic and continuum astronomical observations, it is of great interest to study the atmospherically distorted shape of the telescopic point spread function and the resulting cross talk among adjacent pixels. Here we present a model study of anomalous refraction effects by producing simulations of a two-dimensional phase screen located in the aperture plane of the antenna, using the Large Millimeter Telescope as a benchmark. Then we discuss the basic concept and simulate the operation of a tip-tilt compensation method at millimeter wavelengths that would use an aperture plane array of 183 GHz radiometers.

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Bandwidth considerations for tracking through turbulence

Cited by 115 publications

References 4 publications

Feedback control baseline for GTC adaptive optics with NGS

Feedback control baseline for GTC adaptive optics with NGS

Auxiliary free space optical communication project to ensure continuous transfer of data for DAG the 4m telescope

Predicting the effects of anomalous refraction on the telescope point spread function: Tip‐tilt compensation at millimeter wavelengths

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