LBT LGSF: program goals and Phase A plans

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LBT LGSF program goals and Phase A plans

• consensus on program goals
• exploit the scientific competitive edge of
  LUCIFER MOS and wide field imaging
• need reliable, low maintenance system with low
  risks, minimize changes to existing telescope
  systems
• promptly realize ground-layer system (GLAO) 4
  FOV, factor 2 improvement in FWHM and
• 3 in concentration, operability
  significantly above median seeing
• identify upgrade path to on-axis diffraction
  limited performance (SCAO)
• identify upgrade path to wide-field, modest
  Strehl, diffraction limited operation (MCAO)

• consensus on technology
• while Na LGSF has proven to deliver diffraction
  limited operation for SCAO, the currently lowest
  risk/affordable choice for GLAO in terms of
  laser technology is a pulsed Rayleigh system
• projection system should be independent of laser
  technology, be a single projector for each of the
  pupils, allowing both on-axis and off-axis
  projection schemes
• wave front sensors (wfs) should not require
  immediate re-design of AGW units this may
  require that the wfs are outside the AGW units,
  upgrade to MCAO may require redesign of
  AGW/tertiary

• unknowns
• which is the best upgrade path to diffraction
  limited mode ?
• benefit of LGSF to interferometry (given fringe
  tracking issues)
• how fast will a low cost, low maintenance
  Na-laser be available commercially ?
• impact of LGSF on operations commissioning
• tradeoff between PSF stability across field and
  FWHM, predictability of PSF

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deliveries of Phase A

• performance estimates as a function of seeing,
  Cn2(h), constellation of laser stars etc.
• study availability and cost of Na-laser system
• decision on laser system
• opto-mechanical design
• (universal) launch concept
• upgrade paths to SCAO and MCAO and performance
  estimates, including tomography
• impact on telescope, staffing plan
• cost and schedule estimates

phase A schedule June 2007 December
2007 conceptual design review January/February
2008 (review panel to include external
members)
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team responsibilities during phase A