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sub-FITS are FITS files containing images or data (or both) and are created by subsystems throughout KPF.
Some are created by devices (i.e. Archons) and some by dispatchers (i.e. Ca HK Detector dispatcher)
Each sub-FITS is designed to be stand-alone, and contain all of the relevant subsystem information within.
The sub-FITS are assembled together by the FITS Assembler to form a single FITS file per observation
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There is one L0 FITS per observation.
It contains all of the raw data from the observation.
Within HDU 1 it also contains header data from the overall system (i.e. telescope and observatory) that is not contained within the sub-FITS headers
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use it within the sub-FITS filenames (“subsystem-prefix_obsID.FITS”)
This this allows for straightforward assembly of correct files, and the assembler only needs to look at filenames.
place it within the header of each sub-FITS
maintains obsID traceability after the L0 is created and the sub-FITS filenames are lost.
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Directory Structure for FITS Files
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The sub-FITS sub-directories will hold the separate FITS from each subsystem before L0 assembly
The sub-FITS will not be immediately deleted after L0 assembly, but will remain in the directory for one month (TBC) as a backup.
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Final L0 Filename
As per KPF File Names, the L0 Filename expected by the DRP is:
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After each observation, the FITS Assembler pulls images with the appropriate obsIDs from the separate subsystem interim directories
These sub-FITS are then directly copied into the larger L0 FITS, in the correct order, with no modifications.
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