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
Data Members of Chunk:
|startMu||int32||Starting coordinate in Great Circle coordinates|
|endMu||int32||Ending coordinate in Great Circle coordinates|
|ManyAssoc(Segment)||Link to all segments of this chunk (a multiple of 6, depending how many runs make up this segment)|