File Formats

FITS Data Cube

A FITS Data Cube is a FITS image which contains more than 2 axes (NAXES>2). DS9 will automatically detect if a data cube is present and will load all additional images. At the same time, DS9 will display the DataCube dialog box which allows the user to select which 2 image to be displayed.
Example:
$ds9 -medatacube foo.fits # load multiple extension fits file as data cube
IRAF
contains the DETSEC and DETSIZE keywords. See NOAO IRAF Mosaic Data Structures
WCS
each FITS image or FITS bin table must contain a vaild equatorial wcs.
HST WFPC2
valid HST WFPC2 data cube, consisting of 4 planes, along with a fits ascii table containing wcs information.

FITS Mosaic Data Cube

A FITS Mosaic Data Cube is a FITS mosaic image which contains more than 2 axes (NAXES>2). DS9 will automatically detect if a mosaic data cube is present and will load all additional images. At the same time, DS9 will display the DataCube dialog box which allows the user to select which 2 image to be displayed.

FITS RGB

A FITS RGB image may exist as three of FITS images, one FITS file with three extensions, or as a FITS 3D Data cube, with three slices, each representing the red, green, and blue channel. A FITS RGB image may be loaded all a one time, or by the channel. Once loaded, the multiple FITS images are treated as one FITS image.

Example:
$ds9 -rgbimage rgb.fits # load rgb image consisting of one fits file with 3 image exts
$ds9 -rgbcube cube.fits # load rgb image consisting of one fits data cube
$ds9 -rgb -red foo.fits -green bar.fits -blue wow.fits # rgb image from 3 fits images

Split FITS

A split fits is a valid fits file in which two files contain the header and data segments.