Data Archive Server structure and contents
The Data Archive Server (DAS) is a file system containing all
survey data products. It is accessible via
This page mirrors the directory structure of the DAS, explaining
which files are found where. It links to the "data model" descriptions
of individual files. Directory names link to the http location, but
the rsync server uses the same directory
structure. For more details, see the data model for directories.
The root directory contains a number of ASCII parameter files with names
fileList-*.par . These contain lists of all files in the
archive with a CRC checksum for each, and of all files which are
"missing" from the archive (i.e., you may expect to find these, but
they do not exist).
The root directory for imaging. It contains two kinds of
subdirectories: two inchunk directories containing the calibrated object lists, and one
directory for each run/rerun pair
containing the remaining imaging data.
inchunk directories
Download this directory to obtain the complete imaging
catalogues with the best available data and reductions. Be
sure to read the caveats on the calibrated object lists page.
The imaging is done along great circles. A unique covering of the
sky is ensured by dividing these great circles into chunks. Calibrated object
lists for each chunk are stored in subdirectories with names
stripeNN_muMMMMMM_S where NN is the stripe number,
MMMMMM is the starting mu coordinate for that chunk, and
the skyVersion S=1 for the "best"
version.
Download this directory to obtain the complete imaging
catalogues as used to run target selection for the spectroscopic
survey. Be sure to read the caveats on the calibrated object lists page.
Subdirectories as in inchunk_best . For "target" data,
the skyVersion S = 0 .
- /DR2/data/imaging/inchunk_XX/stripeNN_muMMMMMM_S
E.g. /DR2/data/imaging/inchunk_best/stripe09_mu615000_1.
These directories contain the following
- Files
- Subdirectories
- Six subdirectories (1-6), one per camera column, containing
object lists as
tsObj*.fit and
tsField*.fit files.
mask subdirectory containing csv imaging
masks. Note that the csv masks are
generated from the fpM files, which are
stored in the corresponding run/rerun directory (see
below).
run/rerun directories
These directories have names of the form
- /DR2/data/imaging/RRRR/EE/
where RRRR is the run
number and EE is the rerun
number, eg. /DR2/data/imaging/1336/21.
Each run/rerun directory contains the two types of subdirectories.
- Directories which contain only files:
astrom -- results of the astrom pipeline
nfcalib -- results of photometric
calibration
logs -- opBC*.par files
listing bad columns for this imaging run
- Directories with one subdirectory per camera column (1-6),
containing the bulk of the imaging data:
corr -- corrected frames fpC*.fit.gz ,
ie. reduced survey images
Zoom -- fpC*.jpeg images of the
sky in various zoom levels
objcs -- further outputs of photometric pipeline:
- fpAtlas*.fit --
set of pixels belonging to each object in the
calibrated object list (corresponding tsObj
file). See how to
read an atlas image
- fpBIN*.fit --
2x2 and 4x4 binned versions of corrected frames (fpC)
after objects detected on original frame have been subtracted
- fpM*.fit -- full masks
with saturated pixels etc. See how to read
fpM masks. These form the basis for the csv imaging
masks (see above).
- fpObjc*.fit --
object lists in counts and pixels (these become the
tsObj files after photometric calibration and
conversion of scales in pixels to arcseconds, among others)
- fpFieldStat*.fit --
statistics of photometric pipeline processing for a
single field. Basis for tsField files.
- psField*.fit --
Prelimary photometric calibration, as well as final
point-spread-function fit, for a single field. Use
these to reconstruct
the PSF at any position.
Spectroscopic data
spectro2d pipeline output, produced by rerun 20 of the
spectro pipelines: the calibrated spectra. Contains one directory per
plate with name
/DR2/data/spectro/2d_23/PPPP
where PPPP is the plate number (eg. /DR2/data/spectro/2d_23/0644). Each
directory contains one spPlate*.fit file with all
640 calibrated spectra for that plate.
Calibrated spectra (including gif and ps plots) and
classifications, redshifts, and other measured parameters (line fits,
velocity dispersions, line indices). Contains one directory per
plate with name
/DR2/data/spectro/1d_23/PPPP
where PPPP is the plate number (eg. /DR2/data/spectro/1d_23/0644).
Each directory contains two subdirectories:
1d -- contains 640 spSpec*.fit files,
one per spectrum, containing the spectrum and all derived parameters.
gif -- contains gif and ps plots of each spectrum,
with line annotations
Spectra + imaging
See separate page about getting spectra in bulk.
Last modified: Thu Jun 3 16:31:59 CDT 2004
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