FITS headers
GIMP 2.10.30
Operating System: All
Description of the feature
Opening a FITS image, no FITS header is shown.
menu Image, Metadata as now show: Exif, XMP, IPTC tab, but no FITS headers.
Attached an example FIT image with header filled of useful informations.
FITS header is at file image begin, and is composed of N records sized 80 bytes without separator in between. I saw FITS with 109, 144, and 173 records, but maybe can exist other sizes. Last record is "END"+space padding "0x20", next byte is the first image byte.
Each record is pure ASCII text (maybe UTF-8 not sure), composed as so:
NAME (8 Bytes), capital (but not required) ASCII letters
= (1 Byte as 0x3D)
VALUE (up to 71 Bytes), often as so:
a) for numerical values:
the number as ASCII chars (like a printf %d), padded with spaces to 80 B
b) for text values:
the text is usually enclosed in single quotes and padded with spaces to 80 B
Comments for both numbers and text are separated by '/' and are the last part of the "line" to 80 B
Use cases
Telescope cameras and Astronomers save all field image data in FITS header. Ability to see the metadata is necessary for reference and post processing. sample_J00_20201217083143_CAMxx.fit