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

2. Design Philosophy (Optimize Science Impact)‏ FPs notoriously difficult to calibrate, regularize and interpret: iBTFs are unheard of – doesn’t help; How do we tackle “fear of the unknown”? Develop intuitive approach to problem Lots of graphical feed-back – “Picture = 10 3 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 (it’s free)‏ in Brazil ; at SOAR

3. Over-arching Goals (Calibration) ‏ Efficient calibration of FPs require: 1. Calibration sources (line & continuum ; wide-field & point)‏ 2. Slick parallelism determination (daytime only?)‏ FP I & FP P (different procedures & algorithms)‏ Stability of SESO FPs unknown 3. Slick gap (FP order) determination (daytime only?)‏ FP I & FP P (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) ‏ FP I parallelism determination (low-R)‏ SOAR’s 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 FP P parallelism determination (High-R)‏ SOAR’s 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): SOAR’s ISB calibration unit (full-field or fibre-feed)‏ Need at least 2 lines ( 1, 2 …) widely spaced Scan FP I or FP P over FSR Robust algorithm to determine FP gap Determine -calibration (locally)‏ PhotonEtc’s tunable source? ($50k?)‏ FP -stability (periodically through night if nec.)‏ FP I – repeat parallel determination FP P – determine Ring Radius (classic technique)‏ FP I + FP P - tandem (coordinated) scans Needs -calibration for both  I   P but  I =  P  z STEP I  z STEP P

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 Don’t 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 Shift&Add 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 FP I 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: 1. “MOSAIC/NEWFIRM pipeline infrastructure” or 2. “LSST software”