WFAU

Tapes === Store

6 x dual PCs 3GHz Xeons 6 x 1 Tbyte local disks

2 Tbyte ingest buffer10 Tbytes of raw 20 Tbytes of processedWFCAM archive storage

10 Mbytes/s

G-bit network

Data Processing at CASU

ESO

Processing summary

25 Tbytes raw data + 50 Tbytes processed = 2 million 2kx2k images

Processing steps

prepare - ingest, check, MEF, check, index, select, preview, process

linearise - dome sequences, non-linearity < 1%

dedark - combine darks, illumination-dependent 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

Quality Control parameterssky, images, astrometric, photometric

Astrometric Calibration from 2MASS

STDCRMSNUMBRMSper detector

Tabulatedsystematicsfrom stackedresiduals

Photometric calibration

based on 2MASS and derived colour equations

2MASS s:n> 10 in J,H,Ks and 0 < J-Ks < 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

20050902

Nightly photometric zeropoints

Z

Y

J

H

K

Galactic Latitude Galactic Extinction

2MASS - WFCAM non-linearity and Dome flat sequences

Panoramic survey of M33