GLAO Workshop Leiden April 2005 Remko Stuik Leiden Observatory

26 April 2005GLAO Workshop Leiden, April Outline of the talk/workshop Introduction GLAO Projects GLAO Wavefront Sensing concepts GLAO Modeling GLAO Experiments and Verification Conclusions

26 April 2005GLAO Workshop Leiden, April Goal From the workshop proposal “The aim of the workshop is to connect people from various groups working on GLAO-related projects. We hope to evolve a better appreciation of the various GLAO methods proposed, as well as arrive at concrete solutions to some of the particular problems. At the end of the workshop, we hope that we will have clearer guide lines for the implementation of current and future GLAO projects.” Talks Discussion blocks General Discussion Social events

26 April 2005GLAO Workshop Leiden, April What is GLAO? Lower SRHigher SR On-axis ‘Classical’ AOExtreme AO Wide Field GLAOMCAO Only correction of the ground layer Moderate correction Large Field of View (>> MCAO)

26 April 2005GLAO Workshop Leiden, April What do you need for GLAO? Some guide stars –Wavefront sensor scheme Modeling –Atmospheric input –Comparison with ‘real life’ GLAO reconstruction algorithm –How to separate the ground layer? Experimental Verification Collaborating atmosphere –Distribution of the turbulence? –Go to Antarctica?

26 April 2005GLAO Workshop Leiden, April What is your turbulence profile? Many measurement campaigns –What accuracy is required? –Influence of variability on GLAO performance? Slodar profiling by R. Wilson La Palma Paranal

26 April 2005GLAO Workshop Leiden, April How to sense your wavefront? Separation of –Low altitude –High altitude Multiple NGS LGS + NGS Multiple LGS

26 April 2005GLAO Workshop Leiden, April What is needed for modeling and reconstruction? The right tools –Development of GLAO algorithms Virtual tomography? –Closed loop correction terms? Optimal C n 2 weighting? Layer Oriented? How to use the WFS data? –The art of ignoring information The right information –Statistical versus real atmosphere –Variations in the atmosphere

26 April 2005GLAO Workshop Leiden, April Virtual Tomography in closed loop Real DM LGS Virtual layer Virtual tomography idea: 1.Multi-layer tomography (“mcao”) 2.Projection: Virtual Real Closed loop: need correction term to WFS before tomographic reconstruction. Problem: In closed loop, WFSs don’t see the virtual layer at the conjugate altitude where it was calibrated.

26 April 2005GLAO Workshop Leiden, April In practice… Simple example: 1 real DM + 1 virtual DM WFS1 WFS2 WFS3 DM1VDM { G 0, G 1 } = G system matrix calibration: s = Gc 0 where c 0 = [c T, v T ] T CL correction:  = (G 0 T – G 1 )v s = s +  tomography: c 0 = Es projection: c = c + Tv (E = wavefront estimator, T = modal transformation/optional)

26 April 2005GLAO Workshop Leiden, April What can already be verified? Wavefront sensing schemes –Different projects already running Turbulence characterization Modeling –Check performance operational AO systems Comparison with solar AO  See also talks in this Workshop

26 April 2005GLAO Workshop Leiden, April The Program Tuesday April 26 13:00-13:40 Introduction 13:40-17:30 GLAO Projects 17:30-19:00 Wine and Cheese Party Wednesday April 27 09:30-11:45 GLAO WFS Concepts 11:45-13:00 Lunch at Gorlaeus Cantina 13:00-17:00 GLAO Modeling 17:30-19:00 Workshop Diner Thursday April 28 09:30-12:15 Experimental Verification I 12:15-13:15 Lunch at the Witte Huis 13:00-17:30 Experimental Verification II 20:00-21:00 Oort Lecture (Tickets!) There will be NO proceedings There will be a summary of discussions I will collect presentations for the web site

26 April 2005GLAO Workshop Leiden, April Social Program Wine and Cheese Party –Tuesday at the Lorentz Center Workshop Dinner –Wednesday at Hooglandse Huys Dinner + guided tour in old Dutch church Lunch at the Witte Huis –Thursday, 10 minutes walking Oort Lecture by Prof. Anneila Sargent (Caltech) “New Worlds from Dust and Grains” –At the ‘Groot Auditorium’ of the University Leiden (city center) – tickets required Outside the workshop –Queensday Amsterdam—29 april, 19:00-late, 30 april Den Hague—KoninginneNach 29 April, 19:00-late –Flowers Keukenhof Cycling in the area Getting there and back –Bike!

26 April 2005GLAO Workshop Leiden, April Bikes are ideal for transport…

26 April 2005GLAO Workshop Leiden, April Although the weather isn’t always nice…

26 April 2005GLAO Workshop Leiden, April And be careful what you take with you!

26 April 2005GLAO Workshop Leiden, April Any questions? ?