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. The
data following this header will consist of a 256 x 256 (NAXIS1,
NAXIS2 keywords) matrix of 32-bit integers (BITPIX
keyword). To derive the physical value represented, the integer on the
original FITS tape must be multiplied by 10
(BSCALE
keyword). Array members (pixels) that contain a -2147483648 are to be
treated as not containing real data values (BLANK keyword). The
matrix represents KPNO video camera (INSTRUME keyword) pictures
of M87 (OBJECT keyword) taken on the Mayall 4 meter telescope
(TELESCOP keyword). The tape was created on 18 April 1980
(DATE keyword). The date of the observations is not given in this
header; if it were, there would be a DATE-OBS keyword. 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. The blanks in columns 1-8 indicate
that columns 9-80 are to be treated as comment; in this case, they are
blank.