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An Adaptive Optics Road Map Presentation to the AURA Board 7 February 2001

An Adaptive Optics Road Map Presentation to the AURA Board 7 February 2001. A Renaissance in Groundbased IR (even Optical) Astronomy?. Based on presentation to the NSF by Steve Strom. HISTORICAL CONTEXT.

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An Adaptive Optics Road Map Presentation to the AURA Board 7 February 2001

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  1. An Adaptive Optics Road MapPresentation to the AURA Board7 February 2001 A Renaissance in Groundbased IR (even Optical) Astronomy? Based on presentation to the NSF by Steve Strom

  2. HISTORICAL CONTEXT • Adaptive optics: one of the major advances in telescope technology of the 20th century “comparable to the invention of the telescope” • AO systems to date demonstrate its potential to: • Deliver high fidelity, diffraction-limited images • Enable large gains in sensitivity • Reduce the size of instruments • Science enabled by AO is impressive • Imaging lava flows on Io; storms on Neptune; • Imaging accretion disks; precessing jets in YSOs • Resolving Dense galactic and globular clusters • Measuring stellar fluxes; colors in nearby galactic nuclei

  3. However….. • Only 1% – 3% of the sky is accessible to current AO systems • Laser systems are still VERY expensive (and immature technologies) • Detector technologies are still limiting performance • Data reduction techniques need to be better understood (or more widely disseminated) • The full scientific potential of AO has yet to be realized – need 1 – 2 arcminute corrected FOV’s • AO is the enabling technology for the “next generation” of (extremely) large groundbased telescopes

  4. ALFA AO System Sodium Laser result S ~ 0.2, within a factor of 2 of the predicted result (S= 0.4) And now Lick is Getting S ~ 0.7 Progress to “second generation” Adaptive Optics

  5. Unfortunately Sodium Lasers are not a mature technology

  6. State-of-the-art is still complex- Keck’s laser room (one wall)

  7. Conclusions (circa 2001) • We are entering a decade of unparalleled growth in the competitiveness of ground-based O/IR astronomy • Adaptive Optics will be largely responsible for growth • The US and Gemini communities have a unique lead in Adaptive Optics • However the lack of a mature Sodium Laser technology represents an effective “log-jam” in the further development of Adaptive Optics • The problem Gemini faces, in common with other AO programs, is that the non-recurring costs of developing viable, facility class lasers for such systems are currently beyond the resources of any of the major adaptive optics programs • A focused, community wide effort (Gemini, CfAO, USAF) will lead to “turn-key” affordable Sodium Lasers for all grounbased telescopes • This will enable MCAO and the ‘Next Generation’ 30m - 100m telescopes

  8. Some drawbacks of “classical” AO • Simulation on an 8m telescope, H Band (1.6 um) • Atmospheric spatial decorrelation limits effective FOV • AO correction requires a bright star • Sky coverage limited to0.1% - 1% of sky

  9. Some drawbacks of “classical” AO • Variation in Point Spread Function (PSF) across the field of view complicates the quantitative interpretation of observations in dense fields or spatially complex objects

  10. Effectiveness of MCAO Numerical simulations: • 5 Natural guide stars • 5 Wavefront sensors • 2 mirrors • 8 turbulence layers • MK turbulence profile • Field of view ~ 1.2’ • H band

  11. 20 arcsec Modeling verses Data GEMINI AO Data 2.5 arc min. Model Results M15: PSF variations and stability measured as predicted

  12. Quantitative AO Corrected Data • AO performance can be well modeled • Quantitative predictions confirmed by observations • AO is now a valuable • scientific tool: • predicted S/N gains now being realized • measured • photometric errors in crowded fields ~ 2% Rigaut et al 2001

  13. MCAO 1/2 FoV 1/2 FoV AO 0 10 20 30 40 50 60 [arcsec] The Realm of MCAO • MCAO vs CAO: • Field of view, gain in area: J20-80 x, K10-20 x, depending on criteria and conditions. • Photometric performance: photometric accuracy prop to Strehl variations in the field. MCAO ~ CAO / 10, i.e. for accuracy of 5% for CAO, MCAO gets to 0.5% -> 0.01 mag on a CMD.

  14. Distant Galaxies Milky Way programs GSAO Nearby Galaxies PUEO HK Keck ESO Keck Realms of MCAO/CAO MCAO 100 Field of view  [arcseconds] 10 CAO 1 0.05 0.1 0.01 0.005 Photometric accuracy [mag]

  15. First test of tomographic technique • Ragazzoni et al, 2000, Nature 403, 54 • Collected optical data on a constellation of 4 stars • Used tomographic analysis from outer three to predict phase errors of the central star • Tomographic calculations correctly estimated the atmospheric phases errors to an accuracy of 92% • better than classical AO • MCAO can be made to work

  16. Sodium Laser at Chile

  17. The Southern Sodium Layer - Preliminary results February 11, 2001

  18. Unchallenged “NGST class” science ‘03 Laser Development timescales in context 2000 2010 Keck I&II Keck-Inter. NGST ALMA UT1-UT4 VLT-I HET LBT ALTAIR+LGS ALTAIR Gemini-N Hokupa’a Gemini-S MCAO Hokupa’a-II

  19. Laser Development timescales in context 2000 2010 Keck I&II Keck-Inter. NGST ALMA UT1-UT4 VLT-I HET LBT ALTAIR+LGS Gemini-N Hokupa’a ‘03 Gemini-S GAOS MCAO Hokupa’a-II MAXAT CELT OWL GSMT 2nd Generation Telescopes 2000 2010 2015

  20. The Groundbased Scientific Impact- Relative S/N Gain of groundbased diffraction limited 20m,30m, 50m and 100m telescopes compared to NGST Spectroscopy, vres = 30 kms/s S/N x 10 Groundbased advantage 100m 50m 30m 20m NGST advantage

  21. ADAPTIVE OPTICS:A ROADMAP FOR THE NEXT DECADE Based on presentation by CfAO and NOAO/NIO on behalf of the US AO community 27 APR 2000

  22. CHALLENGES • Develop new systems approaches • Increase sky coverage/Strehl through use of LGS • Enable wider fields through use of MCAO • Develop key components • Reliable, high power lasers • Advanced wavefront sensors and deformable mirrors • Fast detectors • Advance understanding of atmospheric turbulence • Understand turbulence; Sodium layer excitation NB: AO advances required for d >> 10m telescopes

  23. TOWARD AN AO ROADMAP • Community workshop held on 13/14 DEC in Tucson • Co-sponsored by CfAO and NOAO • Goals: • Prepare a 10 year roadmap for NSF investment in AO • new systems approaches • systems design issues • technology investments • subsystem developments • software issues • key investment areas and associated milestones • Define a process for implementing/updating the roadmap

  24. KEY TECHNOLOGIES • Proposed Investment: • Concept studies for next generation telescopes • identify the role of AO • Expected Return: • Deeper understanding of the relative priorities of roadmap investments as the decade unfolds

  25. KEY TECHNOLOGIES • Proposed Investment: • develop reliable, affordable sodium lasers (10-50 W) • support R&D on Rayleigh beacons • Expected Return: • greatly accelerated implementation of laser beacons on extant telescopes • wider field correction through use of MCAO • all sky coverage at increased Strehl • extension of AO correction to shorter wavelengths

  26. KEY TECHNOLOGIES • Proposed Investment: • prototyping and testing of wavefront correction elements • curved optics • adaptive secondaries and primaries • transmissive optics • higher order deformable mirrors • Expected Return: • improved optical simplicity and efficiency • reduced thermal background • simplified control systems • enhanced wavefront quality

  27. KEY TECHNOLOGIES • Proposed Investment: • faster, lower noise detectors with more pixels and broader wavelength coverage for wavefront sensing • Expected Return: • improved AO performance with both natural and laser reference beacons

  28. KEY TECHNOLOGIES • Proposed Investment: • advanced numerical methods for computing optimum corrections for inferred wavefront distortions • Expected Return: • enhanced corrected field of view • improved uniformity of image quality over large FOV

  29. KEY TECHNOLOGIES • Proposed Investment: • site-specific monitoring campaigns • instrument packages for real-time support of AO systems • Expected Return: • site characterization for design of optimum AO systems • site selection for next generation telescope(s)

  30. KEY TECHNOLOGIES • Proposed Investment: • model AO system performance • evaluate/validate competitive approaches to modeling • Expected Return: • confidence in predictions from modeling • improved systems approaches

  31. KEY TECHNOLOGIES • Proposed Investment: • support of concept studies and workshops to explore instrumentation design in the AO era • Expected Return: • instrument design and performance matched to opportunities provided by AO

  32. SCHEDULE FOR KEY ACTIVITIES • Site Monitoring • 2001: Begin 3 year program of site testing to provide a database for AO system modeling • 2002: Deploy instruments for Na-layer monitoring • 2003: Deploy initial instruments for monitoring turbulence in real time • 2004: Develop second-generation turbulence monitoring instruments • 2004: Deploy instrumentation for long-term studies at several promising sites for next generation telescopes

  33. SCHEDULE FOR KEY ACTIVITIES • Systems Designs • 2001-2003: Solicit candidate designs for AO systems on 30-m class telescopes • 2004-2006: Test at least two design concepts in the lab or on extant telescopes • 2006-2010: Build one full-up AO system to test advanced concepts on 8-10m telescopes in service of implementation on a 30-m telescopes • 2009-2010: Develop merged design of 30-100m telescope and advanced AO system

  34. SCHEDULE FOR KEY ACTIVITIES • Deformable Mirrors • 2001: Draft plan for developing deformable mirror technologies (~10,000 degrees of freedom) • 2002-2004: Construct modest-sized prototypes • 2005-2007: Build two or three deformable mirrors using scalable technologies

  35. SCHEDULE FOR KEY ACTIVITIES • Wavefront-sensing detectors • 2001: Facilitate foundry runs for fast, low-noise detectors for wavefront sensing in the visible and near-IR • 2002-2003: Take delivery and test in existing AO systems • 2004-2006: Fund and test the most promising technology for 512x512 detectors (for 30-100m application)

  36. Investment Required 10 year plan required 2002 - 2012 DRAFT AO Systems for GSMT will cost ~ $100M

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