WFAU

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Data Processing at CASU
6 x dual PCs 3GHz Xeons 6 x 1 Tbyte local
disks
Tapes Store
G-bit network
10 Mbytes/s
2 Tbyte ingest buffer 10 Tbytes of raw 20 Tbytes
of processed WFCAM archive storage
WFAU
ESO
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Processing summary
25 Tbytes raw data 50 Tbytes processed 2
million 2kx2k images
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Processing steps

• prepare - ingest, check, MEF, check, index,
  select, preview, process
• linearise - dome sequences, non-linearity lt 1
  
• dedark - combine darks, illumination-dependen
  t reset anomaly
• flatfield - weekly/monthly twilight flats,
  stable, internal gain corr
  
• curtain - /-5 ADUs, 4-quadrant symmetry,
  bilinear removal
• skysub - group master skys by time and MSB
  if possible
• combine - interleaves, compute shifts and
  stack dithers
• catalog - detect and parameterise objects
• classify - morphological classification
• astrom - astrometric calibration per
  detector
• photom - photometric calibration per
  pointing
• check - examine QC, reject bad products,
  random inspection

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Quality Control parameters sky, images,
astrometric, photometric
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Astrometric Calibration from 2MASS
STDCRMS NUMBRMS per detector
Tabulated systematics from stacked residuals
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Photometric calibration

• based on 2MASS and derived colour equations
• 2MASS sngt 10 in J,H,Ks and 0 lt J-Ks lt 1
• typically between 100-1000 standards per
  pointing
• required to be stellar on WFCAM and unsaturated
• MAGZPT, MAGZRR, NUMZPT per pointing
• NIGHTZPT, NIGHTZRR per night
• external comparison with UKIRT FS

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Nightly photometric zeropoints
20050902
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Z Y J H K
Galactic Latitude
Galactic Extinction
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2MASS - WFCAM non-linearity and Dome flat
sequences
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Panoramic survey of M33