FITS Header Pane

The FITS Header Pane displays the FITS Format header of the current image in a docking pane for viewing editing keyword names, values, and comments. Edits take effect in the displayed image and appear in the header listing as soon as they are "saved", but they become permanent after the is saved to a FITS file. See Editing the FITS Header for alternative ways to view and edit the FITS header and links in the Related Topics below.

• The FITS Header Pane opens from the Image Window > Edit menu and the button on the Image Tools Toolbar.

Changing Header-Data

Each header line contains three items: a keyword, its value, and an optional comment. These items may be changed by loading them into the text field above the header table (but see Color Coding, below, about header items that may not be edited). The changed value is then saved back to the header table using the [Save] button.

Above the header listing is a text field where header items may be dchanged, if desired. Notice that the [Save] button is initially disabled but is enabled after a header item in the text field has been changed.

Procedure:

• Point at the target line in the header. Right-click to open the menu and then select the target item (keyword, value, or comment). This places the quantity into the field at the top of the pane. After editing the value, click [Save] to save it to the header table and update the displayed image.

• To change only the keyword value, you can double click on the header line as a shortcut for selecting it from the popup menu. After editing the value, click [Save] to save it to the header table and update the displayed image.

• To permanently save the changed header to the image, save the image to a FITS file.

Color Coding

Some header items may not be edited using this method. These disallowed items are shown with a light pink background. For example, the number of columns, indicated by NAXIS1, may not be edited but may be changed using a command like Expand Image.

Keywords Added when Opening the FITS File

When a FITS file is opened, Mira changes or adds some keywords such as BZERO and BITPIX while the image is held in memory. To show the original values from the FITS file, Mira adds four COMMENT keywords at the end of the displayed FITS header (see below). The following four COMMENT lines are added in memory but are removed when the image is saved to a FITS file (note that the COMMENT values depend on the specific image):

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

Related Topics

FITS Format

FITS Keywords

FITS Header Editor

View and Search FITS Header

Editing the FITS Header

List COMMENT Keywords

History Keywords

LIST WCS KEYWORDS

List Statistics Keywords

Image Information Editor

MIRAPROC Keyword

Modify Keywords

Add Metadata

Mira Pro x64 8.83 User's Guide, Copyright Ⓒ 2026 Mirametrics, Inc. All Rights Reserved.