Chunk
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Chunk |
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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.
Aliases: sxChunk
Data Members of Chunk:
| Member Name/Aliases | Datatype | Description |
|---|---|---|
| chunkNumber | int16 | Chunk number |
| startMu | int32 | Starting coordinate in Great Circle coordinates |
| endMu | int32 | Ending coordinate in Great Circle coordinates |
| stripe | int32 | Stripe number |
| exportVersion | char[32] | Export version |
| segment; Segment | ManyAssoc(Segment) | Link to all segments of this chunk (a multiple of 6, depending how many runs make up this segment) |