The FITS Header Editor dialog displays the
FITS Format image header and permits editing
its contents. If the Image Window contains an
Image Set, header information is shown for all
images. You can switch between image set members using the tab
control at the bottom of the window. You can also view the header
and make edits using the
FITS Header Pane.
Header changes affect only the displayed
image. To make the changes permanent in the image file, you must
save the image using the File > Save command or an
equivalent. For further information about editing, see
Editing the FITS Header and
Working with FITS Format.
The FITS Header Editor opens from the
Image Window >
Edit menu when an image is displayed in the top-most
window.
NOTE
This command is available for any non RGB image
regardless of whether it was opened from a FITS format file. For an
RGB image, use the
Image Information Editor command to view the
information header.
Color Coding
This dialog uses light pink and purple colors for
different parts of the FITS header listing. Purple is used in the
second column to visually separate the keyword value from the
keyword name in column 1 and the keyword comment in column 3. Pink
is used in the entire row for keywords that cannot be edited, such
as SIMPLE or NAXIS1. The pink keywords may be changed by various
Mira functions but may not be manually changed using a Mira header
editor.
Original FITS keywords from the FITS file
When opening the image from a FITS file, Mira may
scale the data using the FITS values for BSCALE and BZERO and may
change BITPIX for the image held in memory. To show the original
values from the FITS file, Mira adds four COMMENT keywords at the
end of the FITS header. These are visible in the
FITS Header Pane and FITS Header Editor. They
are stripped from the header when saved to a FITS file. Here are
the four keyword lines with typical values:
COMMENT FITS file opened
with SIMPLE = T
COMMENT FITS file opened
with BITPIX = 16
COMMENT FITS file opened
with BZERO = 32768
COMMENT FITS file opened
with BSCALE = 1
Save your changes
Changes made in the Image Information Editor
dialog do not take effect until you have accepted them by clicking
a button. These changes are made only to the displayed
image(s).
To accept your changes, click
[Apply] or [OK].
To discard all changes, click
[Cancel] before clicking [Apply]. When you click [Apply], all changes made prior to that point are
saved.
NOTE
The header grid shows all values left-aligned, as
this makes the information easier to discern when scanned
vertically. However, FITS format requires numeric keyword values in
the FITS file to be right-aligned. All keyword values are saved
with the correct alignment when the data are stored to the FITS
file.