Adaptive Optics for Large Telescopes最新文献

{"title":"Sodium Guide Star Adaptive Optics System for Astronomical Imaging in the Visible and Near-Infrared*","authors":"D. Gavel, James R. Morris, R. Vernon","doi":"10.1364/aolt.1992.afa3","DOIUrl":"https://doi.org/10.1364/aolt.1992.afa3","url":null,"abstract":"We are building an adaptive-optic telescope system that is based on the use of an artificial guide star created by laser-induced flourescence of the sodium mesospheric layer. This paper discusses the system design for mid-visible to near-infrared compensation of a one meter telescope at Livermore and near-infrared compensation of the ten meter Keck telescope at Mauna Kea. We calculate the expected Strehl ratio and resolution for a 69 channel deformable mirror system and also for a possible 241 channel system upgrade. With the 69 actuator system we expect near diffraction limited resolution, about 0.2 arcsec, with a Strehl ratio of about 0.5 at λ=0.8 µm on the 1m telescope, and resolution of about 0.05 arcsec with a Strehl ratio of about 0.5 at λ=2.0 µm on the 10m telescope. Resolution will be limited by the performance of the tip/tilt correction loop, which uses an off-axis natural guide star as a reference. At Livermore, our design uses an existing high power (1 kW) laser source, which is expected to provide an approximately 6’th magnitude artificial guide star. This strong beacon signal allows a short integration time in the wavefront sensor so that temporal changes in the atmospheric turbulence can be tracked accurately. For Mauna Kea, we explore how the system to be built for the Livermore site would perform in the infrared, assuming a 100 W laser source.","PeriodicalId":428183,"journal":{"name":"Adaptive Optics for Large Telescopes","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116690274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Real-Time Corrected Long Baseline Interferometer System Concept","authors":"R. Vernon","doi":"10.1364/aolt.1992.pd10","DOIUrl":"https://doi.org/10.1364/aolt.1992.pd10","url":null,"abstract":"A design concept and analyis for a long baseline interferometer imaging system that uses real-time higher order wavefront control, tilt and piston control has been developed to: (1) stabilize the fringe field associated with the visibility phases, (2) measure visibility amplitudes and closure phase, and (3) allow investigation of celestial sources beyond 15th magnitude. Pupil plane phase difference control and closure phase measurement on three telescopes is accomplished simultaneously using differential phase modulation and Fourier de composition. Atmospheric wavefromt sensing is accomplished in all three telescopes using Rayleigh scattered 15 watt laser guide stars focused at 20 km. Tilt sensing and correction is accomplished using the imaged source field. A method for obtaining good pupil plane coverage using only three 1 meter apertures is presented. Analysis is performed on the adaptive optics assemblies to trade-off laser guide star power requirements, optical train efficiency, wavefront sensor measuring accuracy, track sensor accuracy, number of wavefront sensor subapertures, deformable mirror actuators and servo bandwidth requirements. Analysis is performed on the piston control subsystem to optimize the measurement of closure phase and visibility amplitude over a narrow spectral bandwidth, to trade-off source irradiance requirements, piston measuring accuracy, and visibility amplitude accuracy.","PeriodicalId":428183,"journal":{"name":"Adaptive Optics for Large Telescopes","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133520990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Real-time Fourier transform image analysis for measuring atmospheric phase errors over large apertures","authors":"R. Dekany, M. Lloyd-Hart, D. Sandler, J. Angel","doi":"10.1364/aolt.1992.awb6","DOIUrl":"https://doi.org/10.1364/aolt.1992.awb6","url":null,"abstract":"Most existing techniques to measure wavefront aberrations rely on single or double integrations of local tilt or curvature. These techniques forfeit accuracy when applied to large apertures, when the number of subapertures needed to span the pupil becomes great. Since a natural star must be used to sense overall tilt, it is useful to consider direct interference methods which exploit the spatial coherence of starlight to make large scale phase measurements as well. Phase information is contained directly in the interference speckles of the far field image. Recently Angel et. al.1 and Lloyd-Hart et. al.2 have demonstrated the use of artificial neural nets to analyze speckle images for phase. Here we present the theory behind an approach to reconstruct pistons in real time using data obtained by Fourier transforming the image-plane interference pattern. The underlying idea behind the approach draws on methods developed for long-baseline interferometry3,4,5.","PeriodicalId":428183,"journal":{"name":"Adaptive Optics for Large Telescopes","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124405660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a fully adaptive coronagraph with a wavefront curvature sensor and membrane mirror","authors":"D. Golimowski, S. Durrance, M. Clampin","doi":"10.1364/aolt.1992.atha3","DOIUrl":"https://doi.org/10.1364/aolt.1992.atha3","url":null,"abstract":"The Johns Hopkins University (JHU) is continuing its development of an Adaptive Optics Coronagraph (AOC) to include a wavefront curvature sensor (WCS) of the type described by Roddier1 and a membrane mirror for full correction of the distorted wavefront. Initially constructed with an image motion compensation system for the removal of wavefront tilt effects,2 the fully-adaptive AOC will retain the high speed tip/tilt mirror of the earlier instrument to complement the membrane mirror in the feedback loop. The complete system is shown schematically in Figure 1. The 91 element membrane mirror (M1) is placed in the recollimated telescope beam at the location of the telescope exit pupil, and corrects for all wavefront aberrations other than tilt. The tip/tilt mirror (M2) removes image motion due to wavefront tilt, and the light is then refocussed by lens L2 onto the occulting mask (M3). This mask, consisting of a small aluminum spot deposited on a clear window, reflects the light of the bright star into the WCS leg of the instrument, while the circumstellar environment is imaged, aberration free, in the coronagraph leg.","PeriodicalId":428183,"journal":{"name":"Adaptive Optics for Large Telescopes","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124186090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Results of Adaptive Correction of Amospheric Piston and Tilt Errors at the Multiple Mirror Telescope","authors":"M. Lloyd-Hart, R. Dekany, D. Wittman, D. Sandler, B. McLeod, R. Angel, D. Mccarthy","doi":"10.1364/aolt.1992.awa4","DOIUrl":"https://doi.org/10.1364/aolt.1992.awa4","url":null,"abstract":"An objective of our adaptive optics research at the 7-m Multiple Mirror Telescope (MMT) is to investigate ways of reconstructing wavefront errors accurately over large spatial scales. Correction of tilt error across and piston errors between each of the six 1.8-m diameter segments of the MMT is sufficient to recover the full diffraction-limited resolution at 2.2 μm of 0.06 arcseconds full width at half maximum1.","PeriodicalId":428183,"journal":{"name":"Adaptive Optics for Large Telescopes","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124192961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An experiment to investigate the isoplanatic angle of the atmosphere in the near infrared","authors":"D. Neal, R. B. Michie, J. Drummond, D. McCarthy, T. Mckechnie","doi":"10.1364/aolt.1992.amd2","DOIUrl":"https://doi.org/10.1364/aolt.1992.amd2","url":null,"abstract":"Recently there has been considerable discussion of the properties of atmospheric turbulence. The size of the outer scale (L0), and the scaling of the isoplanatic angle with wavelength have been questioned[1]. In order to address these questions, we conducted an experiment to make correlation measurements of the intensities in widely separated binary stars (~ 30 arc sec) as a function of separation.","PeriodicalId":428183,"journal":{"name":"Adaptive Optics for Large Telescopes","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125985166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First-order performance evaluation of adaptive optics systems for turbulence compensation in extended field-of-view astronomical telescopes","authors":"B. Ellerbroek","doi":"10.1364/aolt.1992.atua6","DOIUrl":"https://doi.org/10.1364/aolt.1992.atua6","url":null,"abstract":"A general approach is presented for evaluating and optimizing the degree of atmospheric turbulence compensation achieved by an adaptive optics system employed as part of a extended field-of-view astronomical telescope. This method applies to an adaptive optics system incorporating either one or multiple natural and/or laser guide stars sensed by wave-front slope sensors, a wave-front reconstruction algorithm equivalent to a matrix multiply, a servo control law to temporally filter the output of the wave-front reconstructor, and one or several deformable mirrors optically conjugate to different ranges along the telescope’s line-of-sight. The degree of atmospheric turbulence compensation achieved by such a configuration is evaluated in terms of the residual mean-square phase distortion and turbulence-induced optical transfer function at each point in the telescope’s field-of-view. This evaluation accounts for the combined, interacting effects of the atmospheric turbulence \u0000 \u0000 \u0000 \u0000 C\u0000 n\u0000 2\u0000 \u0000 \u0000 (\u0000 h\u0000 )\u0000 \u0000 \u0000 \u0000 profile and wind velocity profile, wave-front sensor and deformable mirror fitting error, wave-front sensor noise, finite control system bandwidth, and the net anisoplanatism associated with a given constellation of natural and/or laser guide stars. Optimal wave-front reconstruction algorithms are derived which minimize the telescope’s field-of-view-averaged residual mean-square phase distortion. These evaluation and optimization results are first-order in the sense that they neglect diffraction effects and assume that all adaptive optics components are strictly linear. Results for the case of a finite servo bandwidth also require the wave-front reconstruction algorithm coefficients to satisfy a set of linear constraints; the reconstructor must precisely predict the deformable mirror actuator command vector in the absense of sensor noise and atmospheric turbulence. Numerical results are presented for a variety of adaptive optics configurations incorporating either a single guide star, multiple guide stars and a single deformable mirror, or multiple guide stars and two deformable mirrors.","PeriodicalId":428183,"journal":{"name":"Adaptive Optics for Large Telescopes","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133274052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On The Implementation Of Adaptive Optics For Improving Broadband Spectral Response In Michelson Interferometry","authors":"G. Loos","doi":"10.1364/aolt.1992.atub2","DOIUrl":"https://doi.org/10.1364/aolt.1992.atub2","url":null,"abstract":"Beginning with the experiments by Michelson in the 1920's and continuing with more recent research activities around the world Michelson interferometry has evolved into a powerful tool for measuring the diameters of giant stars and separations and orbits of multiple star systems. This paper offers calculations of the wavelength dependent limiting sensitivity achievable using a two aperture interferometer, without or with partial adaptive optics corrections, based upon realistic assumptions in regard to system noise sources. Results are presented for the case of observing resolved stars characterized as spectral type G2V, the spectral classification of the sun.","PeriodicalId":428183,"journal":{"name":"Adaptive Optics for Large Telescopes","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115925079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large Telescopes and Integrated Adaptive Optics for Directed Energy Programs","authors":"D. Wildt, R. Prater","doi":"10.1364/aolt.1992.afa9","DOIUrl":"https://doi.org/10.1364/aolt.1992.afa9","url":null,"abstract":"Since the beginnings of the Strategic Defense Initiative Organization (SDIO) programs in Directed Energy Weapons, specifically high energy laser (HEL) based systems, this organization has supported programs that extend the state-of-the-art in adaptive optics. These concepts have been closely woven with the development of very large mirrors that play an active role in the \"beam control\" adaptive optics system. These mirrors are very lightweight for space application and their demanding design requirements raised early questions about whether scalable technology could even be developed and whether these optics could be economically manufactured. Though the requirements for beam projecting systems are different than astronomical imaging applications, there are enough similar technologies involved that these systems should be of interest to this audience.","PeriodicalId":428183,"journal":{"name":"Adaptive Optics for Large Telescopes","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128363855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Compensation Of Static Atmospheric Turbulence With Far-Field Optimization","authors":"N. Mehta, C. W. Allen","doi":"10.1364/aolt.1992.atuc4","DOIUrl":"https://doi.org/10.1364/aolt.1992.atuc4","url":null,"abstract":"The angular resolution of large ground-based telescopes is limited by local atmospheric seeing. If effects of atmospheric turbulence can somehow be compensated, one can achieve diffraction-limited imaging on ground. Steady progress has been made over the past two decades in adaptive optics technology which promises to provide real-time turbulence compensation.","PeriodicalId":428183,"journal":{"name":"Adaptive Optics for Large Telescopes","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129330078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}