Appnr

image display tool for astronomy

DS9 is an application for astronomical imaging and data
visualization.

DS9 is the modern imtool used by astronomers. It is most
distinguished by its support for displaying images of high dynamic
range (such as 16 bit greyscale FITS files). Whereas many other
tools will only read an approximation to such files, DS9 works in
full precision, and uses various display parameters to map input data
into 8 bit data which can be displayed on the screen.

Available parameters for the mapping include: brightness, contrast,
false color, and nonlinear input mapping (such as logarithm, square
root, square, etc.)

Although it may be useful in other fields, DS9 includes a fair number
of features specific to astronomy. There is an astronomical "name
resolver" which allows a lookup of an arbitrary named object to its
coordinates. Given the coordinates of a field, online archive
servers may be queried, and an image retrieved. DS9 thusly
implements a preliminary "Virtual Observatory".

DS9 is entirely controllable from external programs ("XPA"), which
simplifies complex tasks such as data acquisition, realtime display,
and batch analysis.

If images include WCS (World Coordinate System) keywords, then they
may be "blinked" to search for moving or changing objects.