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Using Foreign FITS Encodings

We saw in the previous section (§16) how to store and retrieve any kind of AST ObjectObject in a FITS header by using a FitsChanFitsChan. To achieve this, we set the FitsChan's EncodingEncoding attribute to NATIVE. However, the Objects we wrote could then only be read back by other programs that use AST.

In practice, we will also encounter FITS headers containing WCS information written by other software systems. We will probably also need to write FITS headers in a format that can be understood by these systems. Indeed, this interchange of data is one of the main reasons for the existence of FITS, so in this section we will examine how to accommodate these requirements.

Subsections

- The Foreign FITS Encodings
- Limitations of Foreign Encodings
- Identifying Foreign Encodings on Input
- Reading Foreign WCS Information from a FITS Header
- Removing WCS Information from FITS Headers—the Destructive Read
- Propagating WCS Information through Data Processing Steps
- Writing Foreign WCS Information to a FITS Header