Metadata and Headers

The metadata of both SpectralCube s and LowerDimensionalObject s is stored in their .meta attribute, which is a dictionary of metadata.

When writing these objects to file, or exporting them as FITS HDUs, the metadata will be written to the FITS header. If the metadata matches the FITS standard, it will just be directly written, with the dictionary keys replaced with upper-case versions. If the keys are longer than 8 characters, a FITS COMMENT entry will be entered with the data formatted as {key}={value}.

The world coordinate system (WCS) metadata will be handled automatically, as will the beam parameter metadata. The automation implies that WCS keywords and beam keywords cannot be manipulated directly by changing the meta dictionary; they must be manipulated through other means (e.g., Manipulating cubes and extracting subcubes).