Image display tool for astronomy

 SAOImage DS9 is an astronomical imaging and data visualization
 application. DS9 supports FITS images and binary tables, multiple frame
 buffers, region manipulation, and many scale algorithms and colormaps. It
 provides for easy communication with external analysis tasks and is highly
 configurable and extensible via XPA and SAMP.
 .
 All versions and platforms support a consistent set of GUI and
 functional capabilities.
 .
 DS9 supports advanced features such as 2-D, 3-D and RGB frame buffers, mosaic
 images, tiling, blinking, geometric markers, colormap manipulation, scaling,
 arbitrary zoom, cropping, rotation, pan, and a variety of coordinate
 systems.
 .
 The GUI for DS9 is user configurable. GUI elements such as the coordinate
 display, panner, magnifier, horizontal and vertical graphs, button bar, and
 color bar can be configured via menus or the command line.