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JWST Telescope Optics: Progress Report. Mark Clampin Observatory Project Scientist Goddard Space Flight Center 217 th American Astronomical Society Meeting. JWST’s Optical Design. 3 mirror anastigmat Elliptical f/1.2 Primary Mirror (PM) - PowerPoint PPT Presentation
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Mark ClampinMark ClampinObservatory Project Scientist Observatory Project Scientist Goddard Space Flight CenterGoddard Space Flight Center
217217thth American Astronomical Society Meeting American Astronomical Society Meeting
JWST Telescope Optics:JWST Telescope Optics:Progress ReportProgress ReportJWST Telescope Optics:JWST Telescope Optics:Progress ReportProgress Report
JWST
JWST’s Optical DesignJWST’s Optical Design
3 mirror anastigmat
Elliptical f/1.2 Primary Mirror (PM)
Hyperbolic Secondary Mirror (SM) creates f/9 intermediate image (6 DOF)
Elliptical Tertiary Mirror (TM) images pupil at Flat Fine Steering Mirror (FSM)
Active Optical System
18 primary mirror segments
6 degrees of freedom + ROC
40 K temperature
Beryllium mirrors
3 mirror prescriptions
JWST
JWST Mirror FabricationJWST Mirror FabricationJWST Mirror FabricationJWST Mirror Fabrication
JWST Mirrors made of beryllium Lightweight and stable at 40 K Brush-Wellman
Machined & lightweighted by Axsys 92% material is removed
Raw Be billet (two mirrors)
Primary segment
TertiarySecondary
Mirrors polished at Tinsley Segment cryo-figure: 20 nm
Ambient Surface Figure Cryo Surface Figure
JWST
What is a Flight Mirror ?What is a Flight Mirror ?Primary Mirror Segment Assembly (PMSA) = Mirror + Actuators
Front Face
Rear Face 6 DOF Actuators
Radius of Curvature Actuator + Strongback
JWST
Mirror Polishing PerformanceMirror Polishing Performance
EDU mirror is designated Pathfinder mirror:
EDU allows timely resolution of processing issues, and optimized processing for flight mirrors
EDU
Flight mirrors
Excellent convergence rate on flight mirrors
JWST
Flight Mirror Cryogenic TestingFlight Mirror Cryogenic Testing
JWST
Flight Mirrors Meeting SpecificationFlight Mirrors Meeting Specification
JWST
Aft-Telescope Optical SystemAft-Telescope Optical System
JWST
First Gold Coated EDU Primary MirrorFirst Gold Coated EDU Primary Mirror
JWST
Coating of Flight Mirrors UnderwayCoating of Flight Mirrors Underway
JWST
Gold Coated Mirror AssembliesGold Coated Mirror Assemblies
JWST
Gold Coatings Exceed RequirementsGold Coatings Exceed Requirements
JWST
Flight Mirror Cryogenic TestingFlight Mirror Cryogenic Testing
JWST
Coated Mirror Figures Meet RequirementCoated Mirror Figures Meet Requirement
JWST
Schedule: Acceptance TestingSchedule: Acceptance Testing
JWST
Predicted Image QualityPredicted Image Quality
• JWST optics are designed to be diffraction-limited at a wavelength of 2 μm
• Preliminary simulations of the OTE using A4 flight mirror data as a template for the primary mirror
• Simulated PSF through NIRCam filters
F444W, F200W, F115W, & F070W
NIRCam pixels are 0.032” (SW) and 0.065” (LW)
JWST
Predicted Image Quality: 2 μm & 4 μmPredicted Image Quality: 2 μm & 4 μm
JWST
Predicted Image Quality: 0.7 μm & 1 μmPredicted Image Quality: 0.7 μm & 1 μm
JWST
Flight Mirror: Schedule for 2011Flight Mirror: Schedule for 2011
• 5 flight primary mirrors completed w/gold coating Acceptance testing under way (vibe & optical testing)
• 13 flight mirrors in final polishing cycle
• Flight Secondary in final polishing cycle
• Flight mirror fabrication program will be completed during summer 2011, with delivery of all flight mirrors !
JWST
• Acknowledgements
Chuck Bowers and Kong Ha
Lee Feinberg and OTE team
at GSFC, BATC, NGAS & QCI