激光引导星自适应光学系统的凯克天文台(14).ppt

Laser guide star adaptive optics at the Keck Observatory,Adam R.Contos,Peter L.Wizinowich,Scott K.Hartman,David Le Mignant,Christopher R.Neyman,Paul J.Stomski,Jr.,and Douglas SummersW.M.Keck ObservatorySPIE Astronomical Telescopes and Instrumentation Conference23 August 2002,Waikoloa,HI,4389-42,Talk Outline,OverviewSky Coverage for LGS and NGS ModesOptical PathNew LGS AO HardwareSystem Upgrades&IssuesLaser Guide StarFutureSummary,Overview,Traditional AO with NGS Bright star in close proximity 1%coverageSodium LGS for nearly complete coverageStill require an NGS,but can be much dimmerKeck II System Upgrades for LGS AOLow Bandwidth Wavefront Sensor(LBWFS)Tip/Tilt Sensor(TTS),using quad-cell APDsSoftware controlLaser system(described in following talk)Scheduled for integration in 2003,Sky Coverage:NGS and LGS,1Bahcall 2Keck Report 208,1996.,NGS,LGS,Optical Path,Highlighted AO Bench Elements:1-Image Rotator2-Tip/Tilt Mirror4-Deformable Mirror6-IR Dichroic12-Sodium Dichroic13-Field Steering Mirrors14,15-Wavefront Sensing Camera and Focus Camera Stage17-Beamsplitter18-Low Bandwidth Wavefront Sensor,Tip/Tilt Sensor&Stage19-Acquisition Camera,LBWFS&TTS Description,Low Bandwidth Wavefront SensorShack-Hartmann lenslet array sensor304 subapertures(240 active)Photometrics 512x512 CCD detectorReadout every few sec.to few min.Tip/tilt SensorQuad-lensFiber-fed APDsMounted on 3-axis tip/tilt stageBeamsplitter cube90%to TTS,10%to LBWFS,System Upgrades&Issues(1),System Upgrades&Issues(2),System Upgrades&Issues(3),1st Laser Propagation(12/01),Laser power 17 WFWHM 1.4”(seeing 1”)Magnitude 9.5,Future,Summary of LGS AO at Keck,Achieved first laser propagationAO upgrades being incorporated for LGSIntegration milestones throughout 2003LGS AO on worlds largest optical telescope will become incredible tool for astronomyFirst operational LGS on an 8-10 m telescope,System Flow&Control,