TABLE  Chunk

Contains basic data for a Chunk

A Chunk is a unit for SDSS data export. It is a part of an SDSS stripe, a 2.5 degree wide cylindrical segment aligned at a great circle between the survey poles. A Chunk has had both strips completely observed. Since the SDSS camera has gaps between its 6 columns of CCDs, each stripe has to be scanned twice (these are the strips) resulting in 12 slightly overlapping narrow observation segments.

Only those parts of a stripe are ready for export where the observation is complete, hence the declaration of a chunk, usually consisting of 2 runs.

chunkIDbigint8 ID_AREAhash skyVersion, stripe, startMu, endMu
skyVersiontinyint1 CODE_MISC0 = OPDB target, 1 = OPDB best
targetVersionvarchar32 ID_VERSIONversion of target software
startMuint4arcsecPOS_LIMITStarting mu value
endMuint4arcsecPOS_LIMITEnding mu value
stripeint4 ID_FIELDStripe number
exportVersionvarchar32 ID_VERSIONExport Version
loadVersionint4 ID_VERSIONLoad Version