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LBT Q3 2007 Engineering
Review
TAL Telescope Alignment.
Highlights and Progress(Q3/2007)
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Completed new alignment plans for rigid secondary and LBC
Procured alignment telescope accessories and mounting brackets in
preparation for Q4 alignment work.
Assessed Laser Tracker technology; selected vendor, awaiting
budget decision.
Determined that the blue hub is tilted to between 2 and 4 arcminutes from September engineering observations.
Confirmed that earlier assumptions on plate scale sensitivity to
mirror separation were out by a factor of ~40 (in reality much 8
microns instead of 350+ microns).
Proposed new single-pass null-test for adaptive secondaries.
Supporting Michael Andersen’s efforts in the AGW unit specification
document.
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Open Issues
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LBC Blue alignment can be improved. Possible to check hub
alignment to GR axis using A-Scope.
“Wall-eye” of PMs and other system flexures need to be
quantified and checked against available correction ranges of
optical elements. Again, the A-Scope set-up for LBC alignment
can give some useful measurements of that.
AGW support.
FPIA sensitivity to focus and other low-order aberrations
uncertain. Quantitative investigation underway with Zemaxmodelled CCD’s.
Awaiting budget decision on laser trackers, otherwise no large
optics purchases anticipated for Q4-Q1.
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Progress
Q2: Finalize LBC alignment procedure and improve image quality to the
point that seeing limited images (on good nights) are achievable.
 Alignment procedure finalized, alignment of LBC Red
currently scheduled for November, possibly some Blue
Hub alignment as well.
Q2: Procure alignment equipment
 Alignment telescope mounts and accessories purchased.
Purchase of Laser Tracker in Q1 ‘08 if approved.
Q2: Finalize and “publish” up-to-date Zemax models of various LBT
modes
 Work in progress, have working models of LBC Red, Blue
and Gregorian modes.
Q2: Continue with investigation of tolerances and compare results to
measured system performance
 Work in progress.
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Progress
Q2: Work with software on collimation/pointing etc.
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No outstanding software support issues, supporting MA
for AGW work.
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Planning
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Schedule
 Alignment of LBC Red currently scheduled for November,
possibly some Blue Hub alignment as well.
 Purchase of Laser Tracker in Q1 ‘08 if approved.
 Alignment of rigid secondary in Q1 ‘08.
 Alignment of tertiary mirrors in Q4 ’07 (goal).
 Assistance of MA ongoing.
 FPIA investigation ongoing.
 Publish global coordinate system for LBT (one exists already).
 Publish various “final” Zemax models.
Resource
 Assistance from Software, Engineering groups as well as various
Germans, Italians and John Hill.
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