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PILOT: Pathfinder for an International Large Optical Telescope -performance specifications. Jon Lawrence. JACARA Science Meeting PILOT Friday March 26 Anglo Australian Observatory. DOME C. The data. South Pole. Turbulence: SODAR (winter 2000/1) DIMM (winter 2000/01)
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PILOT:Pathfinder for an International Large OpticalTelescope-performance specifications Jon Lawrence • JACARA Science Meeting • PILOT • Friday March 26 • Anglo Australian Observatory
DOME C The data South Pole • 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 • 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)
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)
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
CN2 profile Dome C Bad iso= 9.5 arcsec fG = 30 Hz iso= 13.5 arcsec fG = 7 Hz r0= 0.05 m (1.8 arcsec seeing) r0= 0.2 m (0.5 arcsec seeing)
CN2 profile Dome C Good iso= 9.5 arcsec fG = 30 Hz iso= 13.5 arcsec fG = 7 Hz iso= 30 arcsec fG = 2Hz r0= 0.05 m (1.8 arcsec seeing) r0= 0.2 m (0.5 arcsec seeing) r0= 0.7 m (0.15 arcsec seeing)
CN2 profile Mauna Kea iso= 9.5 arcsec fG = 30 Hz iso= 13.5 arcsec fG = 7 Hz iso= 30 arcsec fG = 2Hz iso= 2 arcsec fG = 50 Hz r0= 0.05 m (1.8 arcsec seeing) r0= 0.2 m (0.50 arcsec seeing) r0= 0.7 m (0.15 arcsec seeing) r0= 0.20 m (0.50 arcsec seeing)
Atmospheric parameters seeing (arcsec) isoplanatic angle Greenwood (arcsec) Frequency (Hz) Mauna Kea 0.50 2-3 50 Dome C 0.15 - 0.50 10-30 2-10
Atmospheric parameters seeing (arcsec) isoplanatic angle Greenwood (arcsec) Frequency (Hz) Mauna Kea 0.50 2-3 50 Dome C 0.15 - 0.50 10-30 2-10 ? ?
Adaptive Optics object guide star to tip-tilt secondary tip-tilt control telescope optics centroid sensor dichroic beam splitters deformable mirror image camera wavefront control wavefront sensor wavefront analysis
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)
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
Strehl ratio - V band On-axis low order DCG DCB MK
Strehl ratio - K band (tip-tilt correction) Off-axis On-axis DCG DCG DCB DCB
Uncomp DCB Uncomp DCG Diff lim 2m
Uncomp DCB Uncomp DCG DCB off-axis DCG off-axis on-axis Diff lim 2m
Uncomp DCB Uncomp MK Uncomp DCG DCB off-axis DCG off-axis Gemini altair Diff lim 8 m on-axis Diff lim 2m
Sky emission MK Emission = 5% @ 0° C
Sky emission SP Emission = 5% @ -63° C
Sky emission DC Emission = 5% @ -66° C
Relative integration time : 8m MK versus 2 m DC PILOT diffraction limit
Relative integration time : 8m MK versus 2 m DC PILOT Seeing limit - extended object
Relative integration time : 8m MK versus 2 m DC PILOT Seeing limit - extended object
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
V band imaging - AO on Point source ext object
Point source K band imaging - tip tilt ext object
Point source N band imaging ext object
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