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PILOT: Pathfinder for an International Large Optical Telescope -performance specifications JACARA Science Meeting PILOT Friday March 26 Anglo Australian Observatory Jon Lawrence
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The data Turbulence: –SODAR (winter 2003/4) –MASS (winter 2004) –DIMM (summer 2003/04) Sky temperature and opacity –SUMMIT (winter 2003/4) –MIR FTI (summer 2003/4) Met data –COBBER (winter 2003/4) –ICECAM (summer 2003/4) –AWS (winter 2004) –met balloons (summer 2000-04) Turbulence: –SODAR (winter 2000/1) –DIMM (winter 2000/01) –microthermals (winter 1996) Sky temperature and opacity –SUMMIT (winter 2003/4) –MIR FTI (summer 2002/3) –MISM (winter 1998) –NISM (winter 2000) Met data –AWS –met balloons DOME C South Pole
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Seeing Data Dome C - 2002/3 DIMM summer 2002: median seeing 1.2 arcsec (Aristidi et al, 2003) SODAR summer/ winter 2003: median seeing ~0.08 arcsec (33 % floor 0.05)
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Seeing Data Dome C - 2003/4 DIMM summer 2003/4: data not yet reduced median seeing < 1.1 arcsec (~0.4-0.7 arcsec) isoplanatic angle ~ 10 arcsec
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C N 2 profile Dome C Bad r 0 = 0.05 m (1.8 arcsec seeing) r 0 = 0.2 m (0.5 arcsec seeing) iso = 9.5 arcsec f G = 30 Hz iso = 13.5 arcsec f G = 7 Hz
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C N 2 profile Dome C Good r 0 = 0.05 m (1.8 arcsec seeing) r 0 = 0.7 m (0.15 arcsec seeing) r 0 = 0.2 m (0.5 arcsec seeing) iso = 9.5 arcsec f G = 30 Hz iso = 30 arcsec f G = 2Hz iso = 13.5 arcsec f G = 7 Hz
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C N 2 profile Mauna Kea iso = 2 arcsec f G = 50 Hz r 0 = 0.20 m (0.50 arcsec seeing) iso = 9.5 arcsec f G = 30 Hz r 0 = 0.05 m (1.8 arcsec seeing) iso = 30 arcsec f G = 2Hz r 0 = 0.7 m (0.15 arcsec seeing) iso = 13.5 arcsec f G = 7 Hz r 0 = 0.2 m (0.50 arcsec seeing)
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Atmospheric parameters seeing (arcsec)isoplanatic angleGreenwood (arcsec)Frequency (Hz) Mauna Kea0.50 2-350 Dome C 0.15 - 0.5010-30 2-10
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Atmospheric parameters seeing (arcsec)isoplanatic angleGreenwood (arcsec)Frequency (Hz) Mauna Kea0.50 2-350 Dome C 0.15 - 0.5010-30 2-10 ? ?
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Adaptive Optics wavefront sensor wavefront analysis wavefront control centroid sensor dichroic beam splitters to tip-tilt secondary image camera telescope optics guide star object tip-tilt control deformable mirror
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PILOT AO systems Tip-tilt –tip-tilt mirror + quad sensor Low Order AO –ds=0.3 (30-50 actuators) High Order AO –ds=0.08 (500-1000 actuators)
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PILOT AO system performance Low Greenwood frequency: –lower feedback loop frequency –higher integration time –fainter stars lower SNR/bandwidth errors Large isoplanatic angle –larger fields –brighter stars low anisoplanatic error Better seeing (lower r0) –less actuators lower fitting error
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Strehl ratio - V band On-axis low order DCG DCB MK
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Strehl Ratio
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Strehl ratio - K band (tip-tilt correction) DCB DCG On-axis Off-axis
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Diff lim 2m Uncomp DCB Uncomp DCG
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Diff lim 2m DCB off-axis DCG off-axis on-axis Uncomp DCB Uncomp DCG
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Diff lim 2m DCB off-axis DCG off-axis on-axis Uncomp MK Uncomp DCG Uncomp DCB Gemini altair Diff lim 8 m
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Sky emission MK Emission = 5% @ 0° C
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Sky emission Emission = 5% @ -63° C SP
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Sky emission Emission = 5% @ -66° C DC
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Sky Transmission - NIR/MIR MK
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Sky Transmission - NIR/MIR DC
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Relative integration time : MK versus SP, DC, DA
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Relative integration time : 8m MK versus 2 m DC PILOT diffraction limit
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Relative integration time : 8m MK versus 2 m DC PILOT Seeing limit - extended object
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Relative integration time : 8m MK versus 2 m DC PILOT Seeing limit - extended object
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Possible PILOT Instruments Visible (AO-on) imaging: 4k array (0.03 arcsec/pixel) = 2.3 arcmin FOV NIR wide field imaging JHK bands: 4k array (0.6 arcsec/pixel) = 10 arcmin FOV DF imaging KLM bands: 1k array (0.23 arcsec/pixel) = 4 arcmin FOV MIR imaging N band: 0.5k array (0.7 arcsec/pixel) = 6 arcmin FOV
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V band imaging - AO on Point source ext object
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K band imaging - tip tilt Point source ext object
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N band imaging Point source ext object
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Summary Visible AO system (40-100 actuators plus tip-tilt): –near diff lim for on-axis stars 8-12 mag –off-axis reasonable performance up to 1-2 arcmin –highest ground based resolution!! –mirror figure error is very important < 50 nm rms required –spectroscopy? Near Infrared K band imaging: –tip-tilt correction is enough for near diff lim (0.2-0.3 arcsec) –equivalent to 8m ML telescope for extended object, 5m for point source –wide field or narrow field science? Mid-Infrared imaging: –niche is wide field sensitivity
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