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# 19 Alphabetical listing of all keywords with section references

Below is an alphabetical listing of all keywords used in this document, both new SOLARNET keywords and FITS standard/widely accepted FITS convention keywords.

Keyword origins are defined using a code:
- `N`: New SOLARNET keywords defined in this document
- `S`: Keywords defined in the FITS standard (listed in the FITS standard Appendix C)
- `P`: Keywords defined in Paper I-V and Thompson (2006)[^footnote-18].
- `O`: Other keywords in common use before being specified in this document

Keyword requirements are defined as:
- `all`: Required for all FITS headers
- `primary`: Required for primary header
- `obs`: Required for observation headers
- `optional`: Optional

```{csv-table} Solarnet keywords
:header: >
:   "Keyword", "Origin", "Description", "Required", "Section Reference"
:widths: 5 5 30 5 15
:file: solarnet_keyword_list.csv
```

[^footnote-18]: Some of the WCS keywords defined in these papers are also defined in the FITS standard Table 22

Number of keywords: 223