Quickstart Guide for the TERAPIX T0003 release candidate --------------------------------------------------------- For information about T0003, please visit the Terapix website at http://terapix.iap.fr/rubrique.php?id_rubrique=208 (Home / Activities / Data Release / T0003 Wide and Deep summary) The following articles describe this release: T0003 explanatory table http://terapix.iap.fr/article.php?id_article=556 (coming soon) - Explanation of filenames: Image are constructed on the template: CFHTLS_program_filter_RADEC_release For example: CFHTLS_D_z_100028+021230_T0003.fits.fz D : Deep (W: Wide) z : filter (from u g r i z) Chi2 images were built with several filters 100028 : RA +021230 : DEC T0003 : release number A weight (1/variance) map image is provided for each image. Cf. "Stacked Images" in http://terapix.iap.fr/article.php?id_article=556 - Decompression of images: All FITS images are compressed using Rice compression with the tool imcopy from the cfitsio package (http://heasarc.gsfc.nasa.gov/docs/software/fitsio/fitsio.html). Compression was made with the command (the quotes matter) $ imcopy CFHTLS_D_z_100028+021230_T0003.fits 'CFHTLS_D_z_100028+021230_T0003.fits.fz[COMPRESS]' Images can be decompressed with this command: $ imcopy CFHTLS_D_z_100028+021230_T0003.fits.fz CFHTLS_D_z_100028+021230_T0003.fits Note! 'imcopy' outputs Multi-Extension FITS (MEF) *by default*, even if the compressed image was not a MEF. To avoid this behaviour (and to extract the stack into the primary data unit) you can do this: $ imcopy 'CFHTLS_D_z_100028+021230_T0003.fits.fz[1]' CFHTLS_D_z_100028+021230_T0003.fits Rice compression at CADC: http://cadcwww.hia.nrc.ca/cfht/cfitsio_comp.html - Checksums: Each file (compressed image (.fz) or catalogue (.gz)) has its checksum listed in the file T0003rc.md5 to allow you to check the integrity of the data after download. You can check the integrity of the whole directory with $ md5sum -c T0003rc.md5 To check only one file, Deep/CFHTLS_D_z_022559-042940_T0003.fits.fz for instance: $ grep Deep/CFHTLS_D_z_022559-042940_T0003.fits.fz T0003rc.md5 | md5sum -c Deep/CFHTLS_D_z_022559-042940_T0003.fits.fz: OK To check the whole Deep/D1 directory: $ grep Deep/D1 T0003rc.md5 | md5sum -c NB: the directory substructure has to be identical as the one on the ftp site.