AO_RoadMap

Document Sample
AO_RoadMap Powered By Docstoc
					 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


                                         Adaptive Optics Road Map
          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

                                                          Adaptive Optics Road Map
                  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
                                              Adaptive Optics Road Map
Progress to “second generation”
       Adaptive Optics

      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
                          Adaptive Optics Road Map
Unfortunately Sodium Lasers are
   not a mature technology




                          Adaptive Optics Road Map
State-of-the-art is still complex
  - Keck’s laser room (one wall)




                              Adaptive Optics Road Map
          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                                          Adaptive Optics Road Map
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 to
    0.1% - 1% of
    sky


                          Adaptive Optics Road Map
     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




                               Adaptive Optics Road Map
Adaptive Optics Road Map
            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

                                Adaptive Optics Road Map
         Modeling verses Data
                 GEMINI AO Data
                    20 arcsec




2.5 arc min.




                                M15: PSF variations
                                     and stability
                                     measured as
                                     predicted
                                Adaptive Optics Road Map
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
                        Adaptive Optics Road Map
              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:               MCAO
      photometric accuracy prop to
      Strehl variations in the field.             1/2 FoV
      MCAO ~ CAO / 10, i.e. for
      accuracy of 5% for CAO,                                    1/2 FoV
      MCAO gets to 0.5% -> 0.01                  AO
      mag on a CMD.
                                        0   10   20   30    40    50   60
                                                           [arcsec]


                                                 Adaptive Optics Road Map
           Realms of MCAO/CAO

                             Distant Way GSAO
         100                     Milky
                             Galaxies
                                         MCAO
                                 programs

                                           Nearby
                             PUEO          Galaxies
Field of view 




                              HK
[arcseconds]




                        Keck
                          ESO
           10




                          Keck


                  CAO
         1




                  0.1      0.05     0.01      0.005
                    Photometric accuracy [mag]
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




                                  Adaptive Optics Road Map
Sodium Laser at
     Chile




                  Adaptive Optics Road Map
The Southern Sodium Layer -
     Preliminary results




February 11,
   2001                Adaptive Optics Road Map
Laser Development timescales in context
           2000                                         2010
  Keck I&II Keck-Inter.
    UT1-UT4 VLT-I                            ALMA NGST
     HET    LBT

               ALTAIR
               ALTAIR+LGS
Gemini-N Hokupa’a                        Unchallenged

Gemini-S     Hokupa’a-II   ‘03 MCAO “NGST class” science




                                                        Adaptive Optics Road Map
    Laser Development timescales in
                context
           2000                           2010
 Keck I&II Keck-Inter.
     UT1-UT4 VLT-I                   ALMA NGST
      HET    LBT

               ALTAIR+LGS
Gemini-N Hokupa’a

Gemini-S                  ‘03 GAOS MCAO
                   Hokupa’a-II



                                          CELT            MAXAT
                                          GSMT             OWL
 2nd Generation Telescopes

            2000                            2010            2015
                                          Adaptive Optics Road Map
  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




                                                                         Groundbased
                                                                         advantage
                                                         S/N x 10


                                                         100m




                                                                            NGST advantage
                                                          50m
                                                          30m
                                                          20m




                                              Adaptive Optics Road Map
       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
                                   Adaptive Optics Road Map
                      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



                                                 Adaptive Optics Road Map
             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

                                                   Adaptive Optics Road Map
                   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




                                                       Adaptive Optics Road Map
                  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




                                                       Adaptive Optics Road Map
                    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




                                                      Adaptive Optics Road Map
                  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




                                                     Adaptive Optics Road Map
                  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




                                                    Adaptive Optics Road Map
                  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)




                                                     Adaptive Optics Road Map
                  KEY TECHNOLOGIES

   Proposed Investment:

    – model AO system performance
    – evaluate/validate competitive approaches to modeling

   Expected Return:

    – confidence in predictions from modeling
    – improved systems approaches




                                                    Adaptive Optics Road Map
                  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




                                                     Adaptive Optics Road Map
    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




                                                      Adaptive Optics Road Map
    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




                                                       Adaptive Optics Road Map
    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




                                                     Adaptive Optics Road Map
    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)




                                                        Adaptive Optics Road Map
       Investment Required

 10 year plan required 2002 - 2012




AO Systems for GSMT will cost ~ $100M
                                     Adaptive Optics Road Map

				
DOCUMENT INFO
Shared By:
Categories:
Stats:
views:5
posted:6/26/2011
language:English
pages:37