This header is based on the NRAO anonymous ftp collection of FITS files. There have been some minor revisions, none of which affect required or reserved keywords, to bring the style into conformance with recommended practice.
Internal comments explain most of the keywords in detail.
Note that even though some of the character string values are more than eight characters long, it is possible to obtain the essential information from reading only the first eight characters. There are also five keywords that are neither required nor reserved FITS keywords, those beginning with IPPS- . They illustrate how new keywords can be created for a FITS data set. Note the blank lines.