AST Senior Review Major Recommendations

1
Brazilian Tunable Filter Imager(BTFI)Preliminary
Design Review (PDR)?
BTFI Data Reduction (Keith Taylor)?
USP-IAG Universidade de São Paulo 18-19th June
2008
2
Design Philosophy

• (Optimize Science Impact)?
• FPs notoriously difficult to calibrate,
  regularize and interpret
• iBTFs are unheard of doesnt help
• How do we tackle fear of the unknown?
• Develop intuitive approach to problem
• Lots of graphical feed-back Picture 103
  words
• Lead user through process by the nose
• Heavy use of procedural macros
• Minimize trips to the Nasmyth platform
• Make user feel they are in familiar
  Spectrograph-Land
• Propaganda (catch-phrase is Think Slick)?
• How do we achieve Slickness?
• Inherit code without fear or favour
• French, Canadian, French-Canadian, Australian
  (TAURUS c1980 not available!)?
• Deploy lots and lots of post-doc time (its
  free)?
• in Brazil at SOAR

3
Over-arching Goals(Calibration)?

• Efficient calibration of FPs require
• Calibration sources (line continuum
  wide-field point)?
• Slick parallelism determination (daytime only?)?
• FPI FPP (different procedures algorithms)?
• Stability of SESO FPs unknown
• Slick gap (FP order) determination (daytime
  only?)?
• FPI FPP (different procedures algorithms)?
• Need to iterate on gap determination?
• Slick ?-calibration (how often?)?
• ?-calibrated data-cube for ?-correction
  (daytime, only)?
• 3D flat-fields
• Efficient calibration of iBTF requires
• 1, 4, 5 6 ie much simpler than FPs
  (hopefully!)?

4
Over-arching Goals(Observing)?

• Efficient observing requires
• Slick ITC
• on/off-line
• Slick acquisition
• - Field position ?0, ??, ?? ?STEP
• On-line data assessment (continuously updated
  during acquisition)?
• SNR(?,time) in multi-RoIs
• On-the-Fly data reduction (next integration
  time-scale)?
• for acquisition assessment and immediate feedback
• Pipe-line data reduction (next night)?
• State-of-the-Art
• Off-line data reduction (for the anally
  retentive)?
• Toilet paper not supplied
• Archiving
• See comments by Chris Smith (NOAO)?

5
Strategies to achieve goals(FP Parallelism)?

• FPI parallelism determination (low-R)?
• SOARs ISB calibration unit (with fibre-feed
  modification)?
• NB Small gap no by eye method
• Use 4 corner-mounted (flexure) fibres
• Scan rapidly over line determine 4 ?-centroids
  iterate controller (x,y) offsets until 4
  ?-centroids are equal ? parallel
• FPP parallelism determination (High-R)?
• SOARs ISB calibration unit (wide-field)?
• Mexican (hat)trick?
• 4 prisms in pupil filter wheel
• or Pupil re-imager (practicality?)?

6
Mexican (hat)trick
Left the FP is parallel. Right is not
PUMA
7
Further strategies to achieve goals

• FP gap/order determination
• Calibration sources (line)
• SOARs ISB calibration unit (full-field or
  fibre-feed)?
• Need at least 2 lines (?1, ?2 ) widely spaced
• Scan FPI or FPP over FSR
• Robust algorithm to determine FP gap
• Determine ?-calibration (locally)?
• PhotonEtcs tunable source? (50k?)?
• FP ?-stability (periodically through night if
  nec.)?
• FPI repeat parallel determination
• FPP determine Ring Radius (classic technique)?
• FPI FPP - tandem (coordinated) scans
• Needs ?-calibration for both
• ??I ? ??P but ??I ??P ? zSTEPI ? zSTEPP

8
Yet further strategies to achieve goals

• iBTF calibrations
• Determine ?-calibration (single order should
  be simple)?
• Determine ?-map (1D)?
• Slick ITC on/off-line
• Includes models of all instrument detector
  modes
• Includes all sky params (sky brightness, moon,
  extinction etc)?
• Includes magnitude or surface-brightness switch
• On-line data assessment (during acquisition)?
• EMCCD (amp. mode) view SNR increase on-line
• Dont have to wait for next CCD read-out
• On-line z-compressed image (cf TAURUS IPCS
  c1980)?
• Select RoIs (4-6) interactively
• Assess SNR of ?-profiles (not ?-corrected)
  on-line

9
Data Reduction (at last)

• Preliminaries (during afternoon, for all
  configs.)?
• ?-calibration (FPs and/or iBTFs)?
• ?-map (FPs and/or iBTF)?
• 3D flat-fields (FPs and/or iBTF) - ?-corrected
• Acquisition protocols
• 3D data-cubes recorded as individual 2D frames
• OtF data-cubes are not necessarily archived
• On-the-Fly (during immediately after
  acquisition)?
• CR rejection (sigma clipping) on each individual
  z-frame
• ShiftAdd into data-cube taking into account
• Flexure determination (at least once per pass
  through data cube)?
• Guiding corrections (gaussian fits to bright
  stars)?
• Interactive 2D gaussian fitting to field stars
• Interactive ?-profile fitting and SNR
  determination
• Applying ?-correction on each RoI

10
The Pipe

• Post-acquisition processing (next day)?
• Flat-fielding (2D) individual frames from
  Twilight?
• CR rejection (median rejection over 3 frames)?
• Shift Add (x,y,?) into data-cube
• ?-correction
• 3D flat-field correction
• ?-calibration
• Sky-subtraction (in 3D - mainly for iBTF and FPI
  modes)?
• Flux calibration (assuming calibration sources
  have been observed)?
• ?-profile function fitting
• Adaptive binning
• Wavelet analysis (?)?
• 2D maps of flux, velocity, line-width etc.
• Rotation curve fitting (in your dreams!)?

11
The Archive(email between Steve Heathcote /
Chris Smith)?

• Steve Needs to be able to swallow
  40GBytes/night of data and transport it back to
  the archive?
• Chris Yes.  We are committed to producing a
  "Data Transport System" (DTS) interface that can
  swallow at least the 300-400GB/nights by 2010
• Steve What software/hardware they will need for
  running this kind of pipeline.
• Chris
• Hardware Basic Linux cluster, being a rack of
  1U units, each sporting 1 or 2 quad-core CPUs
• Software architecture options
• MOSAIC/NEWFIRM pipeline infrastructure or
• LSST software